On a recent Saturday morning, Broadway actress Jennie Harney was awakened by a phone call with a voice on the other end asking, “How do you feel about an adventure today?”

A few hours later, she was at a New York airport. That evening, she was in San Francisco, ready to go on stage, if needed, as one of the three Schuyler sisters in “Hamilton.”

This is the life of a universal standby in “Hamilton,” the musical based on the life of U.S. founding father Alexander Hamilton. The show has five universal actors ready to fly cross-country and perform in any of its three productions, in New York, Chicago and San Francisco, whenever a regular cast member can’t go on.

“Your job is to be prepared for emergencies,” Harney said.

Nicknamed the “Universal Schuyler,” Harney covers the main roles of Angelica, Eliza and Peggy Schuyler, while the other actors are “swings,” covering five or six ensemble roles.

The show concludes its San Francisco run on Saturday, and the universal actors will add Los Angeles into their rotation when the production resumes there on August 11.

While the “Hamilton” productions are largely the same across the three cities, Antuan Raimone, one of the universal swings, said his job feels more like covering 18 roles because of the different stage dimensions, which change where he has to stand and how he moves. He also has to remain cognizant of the nuances cast members in each of the productions bring to their roles.

Jennie Harney dressed as Eliza Hamilton in San Francisco. Courtesy of Jennie Harney

When Harney later went on in San Francisco, she had to contend with performing the role of Eliza for the first time. And as Eliza, she had to quickly develop a passionate connection with Alexander Hamilton and a sisterly bond with two actresses she had just met.

“There’s just no time. You have to get in there and do your job and pretend that they’re your best friends,” Harney said.

“Hamilton” chose to employ five jet-setting actors, rather than the more traditional option of vacation swings —actors who come in for prescribed periods of time — because of the time it takes to onboard a new cast member. It takes an average of four to six weeks to learn one role in the rapid-paced show, and six weeks to build a set of costumes.

A vacation swing could decide not to come back the next time around, which would mean the production’s investment of time and money is for naught, said Jason Bassett, production supervisor across all “Hamilton” shows.

“Given that ‘Hamilton’ can afford to keep somebody on staff full time, it was well worth our while,” Bassett said.

“Hamilton’s” Broadway production brought in more than $3 million last week, with premium tickets going for $849, according to the Broadway League.

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“Jersey Boys” had one cross-country swing when it had multiple productions running, and Bassett said “Hairspray” also relied on such swings, but the role of a “universal standby” is relatively rare, as the notion is predicated on a show’s having multiple simultaneous productions.

The job may sound stressful, but Harney said she finds the experience of popping in and out of cities and casts “thrilling.”

She is getting married next year and planning to move, so she leapt at the chance to join the cast of a popular show that is expected to be a long-running one. “It was a big priority to me to have that stability and knowing that I’m going to have a job that’s not going to close,” Harney said.

For Raimone, who is 37 years old, the fact that he typically does not go on for eight shows a week, as he would in a traditional ensemble role, means that he is not overextending his body. In the long term, this mean he’s able to lengthen his dance career. “I love dancing, and I love performing, but I’m also aware that the body can only do what it can do for so long,” he said.

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Typically, Bassett tries to schedule the swings and standby, Harney, with a month’s notice. Each cast has its own in-town swings and standbys, but if they all go on at the same time or someone is on vacation or injured, the universal actors are needed.

If there’s enough notice, the show will FedEx all of the actor’s costumes, which can mean a “fleet” of five to seven boxes traveling ahead of them, said Raimone.

“Even an M5 [ensemble member], who is James Reynolds, has seven different coats and capes,” Raimone said.

In an emergency, however, the actor is sent to the airport with a giant suitcase of costumes.

Harney and all of the swings are based in New York, and they have to be at the theater in whatever city they’re in for every show. When they travel, the show pays for the flight, covers housing and provides a per diem for meals and other expenses.

Because of these perks, and the fact that he sublets his apartment when he’s away for long stretches, Raimone has learned that being out of town actually helps him save money. “It is, in essence, more financially beneficial for me to be outside of New York,” Raimone said.

The show also encourages the actors to sign up for frequent-flier miles and allows them to pick the airline when possible.

And time in flight offers a good opportunity to study up on the role, as the actors have access to videos of each city’s production of “Hamilton.”

To prepare for each Schuyler sister, Harney said she’s created a binder with color-coded index cards — coordinated with each sister’s main costume color — as a “cheat sheet” for every number in the show. She began her studies by isolating the show song by song for each role, making notes on movement and the props involved.

“I can’t even tell you how many times I’ve watched ‘Helpless’ and ‘Satisfied’ just to watch traffic patterns,” Harney said.

On the flip side, Raimone said he’s earned the nickname “Magic” because of his ability to watch choreography a few times and memorize it. “I am a freak,” he said.