The woman who ended up persuading a conservative member of Congress that President Donald Trump should release his tax returns didn’t use to consider herself an activist.

When Trump was elected, though, Sara Walters, a consultant in Gainesville, Florida, felt drawn to oppose his agenda. Her involvement eventually led to a brief meeting in February with her member of Congress, Rep. Ted Yoho.

Walters talked to Yoho for just 15 minutes, but she managed to persuade the Tea Party–supporting congressman from a heavily Republican district. Yoho had initially voted against a bill that would force presidents to release their tax returns. In April, he flip-flopped, signing on as a co-sponsor of the legislation — and told a town hall audience of more than 500 that Walters had changed his opinion.

Walters’s story should be heartening for the anti-Trump activists flooding Congress members’ phone lines. A SurveyMonkey poll in early March found 31 percent of self-described liberal Democrats had written to members of Congress since Trump was inaugurated, and 59 percent said they planned to do so over the next two years.

But whether the constituents in question are liberals furious at Trump or conservatives outraged over Obamacare, it’s easy to be skeptical: Can ordinary people really make a difference? Gerrymandering means members of Congress rarely face legitimately contested elections. Super PACs and interest groups wield tremendous influence on legislators. Can letters, phone calls, or meetings really change someone’s mind?

Yes, say current and former members of Congress, pointing to specific constituents who’ve influenced them over the years. But they say some strategies of persuasion work better than others. Here’s what they think works.

Meet in person

As satisfying as it may be to take part in large, organized campaigns with groups of like-minded individuals — letter-writing drives or mass-circulated online petitions, for example — those are not always the most effective ways to make a difference, legislators say.

“Form letters, these postcards that people sign in the mall and then send them in, that’s not that impactful,” said Jason Altmire, a centrist Democrat who represented Pennsylvania’s Fourth District in Congress for six years.

More compelling are in-person meetings with representatives or their staff. Getting a meeting on the calendar can be difficult, but patience is key. “Just ask and be willing to work around our schedule,” said Zach Bunshaft, a staff assistant in the office of Rep. Susan Davis (D-CA).

A willingness to wait is how Walters, the Gainesville activist, ended up getting one-on-one time with Yoho. After Trump was elected, Walters, who works in employee education, got involved with the local chapter of Indivisible, a newly formed progressive group. Every week during her lunch break, starting four days after inauguration, Walters drove to Yoho’s office for “Resist Trump Tuesday.” On February 20, she learned Yoho was in town that day — but all of his appointments were booked.

She told his staff that she’d like to speak to him, and that she was willing to wait. About 30 minutes later, when another constituent’s appointment ended early, she got her meeting.

Tell a story and build a relationship

Once your meeting is set up, lawmakers say, it helps to demonstrate your connection to the issue.

“What’s most effective is having a passionate, credible story,” Altmire said. He points to those who advocate on behalf of disease funding as among the most effective individuals and groups he meets with.

In one case, a family with a child who had Type 2 diabetes met with Altmire not long after he was first elected. The boy was about 10 at the time, Altmire said. Over the next six years, Altmire watched him grow into a teenager and an athlete, and listened to the family’s stories about dealing with the disease.

“And I’m a parent,” Altmire said, “so it just hits you: This is something that this family and this kid [are] going to have to deal with for the rest of their lives.”

Since then, he’s tried to advocate for increased funding for diabetes causes, writing letters to colleagues on the appropriations committee, Altmire said.

Byron Dorgan, who served as a North Dakota senator for 18 years, echoes this sentiment. He told Vox’s Sarah Kliff several weeks ago that the reason he lobbied for the Affordable Care Act’s ban on lifetime limits for health insurance was because of a particular constituent.

Brenda Neubauer’s son had hemophilia, a blood disease that required expensive and frequent injections. Before the ACA passed, insurance regulations allowing for lifetime limits on the amount of treatment insurance could cover meant that Neubauer’s son would run out of benefits by the time he was 16, she estimated. So she continued to set up meetings, to send Dorgan medical bills and photographs, and her story made an impact.

“She caught my attention, I cared about it, and it became personal,” Dorgan said.

“She caught my attention, I cared about it, and it became personal”

Then comes the follow-up. It’s rare than any single meeting can produce tangible change, but building a continued relationships over time can make the difference.

“There’s nothing more effective than sitting across from a constituent when they’re suffering,” Altmire said. “It’s heart-wrenching to have to make these decisions, and then over time, you get to know these people and they become friends. They come into your office and you can see the progression from year to year, and it really makes a huge difference in your support of those programs.”

Do your research, and let your representatives do theirs too

When planning for a meeting with your member of Congress, don’t assume that he or she will know all the intricacies of the issue you’d like to discuss.

“I ask people if it’s a policy issue… to give me some information on the subject prior to our meeting so I can research it,” Rep. Walter Jones (R-NC) said. “There’s some issues you know ahead of time, and many issues that are in a subject area I’m not that familiar with, and I’d like to feel that I can have enough information that I can sit down with you and have a meaningful conversation.”

Representatives probably already know the political outcomes resulting from supporting or opposing a piece of legislation. The best arguments, they say, are about how their decision would affect you personally, and why they should back your point of view.

That’s how a constituent eventually changed Altmire’s mind on the Employee Free Choice Act in 2007. The bill would have made it easier for workers to establish unions. Most Democrats and unions supported the bill, whereas Republicans and business interests argued against it.

When the legislation was introduced, Altmire supported it in the House Committee on Education and the Workforce. On the House floor, he said it would “benefit working families across this country.” But back in his district, Altmire spoke with Bill Rackoff, the owner of a local company that made tools for metal processing. Rackoff was a Republican who hadn’t supported Altmire, but he was able to convince him to oppose the legislation by arguing that it was bad policy that would affect his business.

“He made a very persuasive case,” Altmire remembers. “He’s a guy working in the steel industry in Pittsburgh. And obviously the union issue is very important in that neck of the woods. And he made a case that it was bad legislation and it would hurt his business and I was on the wrong side, and I agreed with him.”

When the bill came up again a couple of years later, Altmire didn’t support it, and the Democratic leadership and union interests weren’t pleased. Nonetheless, Altmire continued to oppose it.

“I don’t think my argument was based on a political view,” Rackoff recalls of his exchanges with Altmire. “What we talked about wasn't a political standpoint; it was really about fairness.”

If at first you don’t succeed...

No matter how personal the issue and how convincing an argument you make, there will still be times when your representative will not take your side. In those cases, try to have him or her explain where the disagreement is, so something productive can come from your conversations.

“We as an office take very seriously the communications that we receive from our constituents,” Jones said. “And we’re going to make sure that that constituent knows if I differ or disagree with their position, why.”

Members of Congress are elected as representatives of their districts, not as direct voices for their constituents’ thoughts and opinions. This tension, which dates back to America’s founding, is present in every major decision Altmire makes.

“Are you electing somebody to do exactly what the district wants?” Altmire asked. “Or are you electing somebody to be thoughtful and get to know the district, and cast a vote on their behalf knowing that you know a lot more about it than anyone in the district knows?”

Rackoff, the constituent who successfully convinced Altmire to change his vote, sees failure as a part of the process.

“I meet with my representatives or senators or their staff to articulate the views I have about certain issues, and explain to them through the force of logic how to think about the issues,” he said. “Sometimes it works, and sometimes it doesn’t.”

In Walters’s case, it seemed to have worked. Months of showing up at Yoho’s office and laying the groundwork with his staff led to an in-person meeting. She did her research, had a specific “ask,” and clearly and deliberately explained her reasoning.

“[The meeting] went really well, probably better than I imagined talking with a Republican representative that I don’t agree with on stuff,” Walters said. Yet even she didn’t think much would come from it. “[Yoho] said he’d think about it, and honestly I thought he wouldn’t do anything about it.”

“I think there’s value in our elected officials understanding when people aren’t happy”

When Yoho mentioned Walters’s name at a town hall meeting nearly two months after they first met, explaining how she’d changed his mind, she wasn’t even there, as she had to watch her kids at home. She learned that she’d been name-dropped via a surge of Facebook posts on her wall, but still her shock and pride at the announcement was palpable. And she hopes the experience shows the value of conversation, not just protest.

“There’s some people whose personalities are more suited to coming out to the protest and holding up signs, and I think there’s value in that,” she says. “I think there’s value in our elected officials understanding when people aren’t happy.”

“But I feel like there’s also value for those of us who want to say, ‘Yeah, I’m not happy, but here’s why,’” she continued. “And I’m going to go in there and meet with people that might not agree with me, and I’m going to try to find common ground in order to change policy.”

While some may have interpreted a victory like Walters’s as a chance to take a break, she’s pushing ahead with full force, asking that Yoho sign a discharge petition to move the bill to require the president’s tax returns out of committee.

“Then, of course, my next ask would be for Yoho to vote YES on HR 305,” she wrote. “If it passes, then there’s an identical bill sitting in the Senate.”