WASHINGTON -- Following an interview with President Donald Trump on CBS News' "Face the Nation," questions regarding Mr. Trump's understanding of key policy issues remain -- even after his 100th day in office.

"CBS This Morning" co-anchor Norah O'Donnell says it's clear that Mr. Trump still has much work to do in figuring out just what needs to happen to make a Republican health care bill pass after House GOP leaders delayed a vote last week on a revised version of the bill, failing to secure the support necessary to conduct a successful floor vote.

Mr. Trump told "Face the Nation" host John Dickerson Saturday that "we have a clause that guarantees" pre-existing condition coverage in the bill, and that the bill "has evolved."

"This bill is much different than it was a little while ago, okay?" Mr. Trump said.

But O'Donnell suggests that Mr. Trump still does not fully understand what the revised health care plan entails.

"His lack of facility with understanding what might be in the new repeal and replace Obamacare, it's part of the frustration so we want to know so much but i'm not sure the president is in the position to tell us that much," said O'Donnell.

"He is the champion of the forgotten man and woman, but does he know how his policies are going to affect the forgotten man and woman, what are those policies and I think that's really the journalist challenge that we face over the coming years, what becomes the process of the legislation when something comes out?" O'Donnell added.

O'Donnell noted that a key question is who is driving policy within the Trump White House on the domestic and national security fronts.

"We know that there are multiple centers of power but it affects relations with Congress and I've said this before, the Republicans have a historic opportunity for change, it is so rare for the party to control the executive and the legislative branch," says O'Donnell.

"CBS This Morning" co-anchor Charlie Rose echoed O'Donnell's view that much work is ahead for Mr. Trump -- and that questions remain.

"Clearly there's many Donald Trump's, we know that," said Rose. "Clearly he has changed the presidency but I want to know how the presidency has changed him and the opinion he has changed and what impact it will have on his future and the country's future."

More coverage of President Trump's interview with "Face the Nation" and his first 100 days in office will air Monday on "CBS This Morning," which will broadcast live from the East Room of the White House.