Donald Trump’s new campaign manager Kellyanne Conway says the Republican nominee is having his best week so far in his campaign, and Republican National Committee chairman Reince Priebus agrees.

"This is the best week, I think, so far in the Trump campaign," Conway said on ABC's "This Week." "Mostly because he's able to be himself, the authentic Donald Trump."

Trump brought Conway and Breitbart News’ Steve Bannon in to run the campaign amid declining poll numbers and a controversy over former campaign chair Paul Manafort's ties to Ukraine's former regime. Manafort resigned Friday.

The staff changes brought a notable shift in tone. On Thursday, the Republican nominee made a rare expression of regret for unspecified past comments that have caused people “personal pain.”

"Sometimes, in the heat of debate, and speaking on a multitude of issues, you don’t choose the right words or you say the wrong thing. I have done that, and believe it or not I regret it," Trump said in North Carolina. "I do regret it, particularly where it may have caused personal pain.”

Pressed by ABC’s George Stephanopoulos on whether the expression of regret would lead to an apology to either the family of fallen U.S. military service member Humayun Khan or Sen. John McCain, Conway demurred.

“He's expressed his regret publicly and said, if I have caused you personal pain -- that can include me, that can include you -- that he regrets that,” Conway said.

Trump’s new tone and his increased emphasis on policy positions drew favorable reviews from the head of the Republican Party.

On "This Week" GOP Chairman Priebus predicted Donald Trump's new "style" is going to lead to a boost in the polls.

"I think he's had a great week, I think he's been on message, he's shown maturity as a candidate," Priebus said, adding, "I think that he's getting into a groove."

"I think what you're going to see is these polls beginning to tighten in the next couple weeks, and by Labor Day or thereafter I think you're going to be back to an even race if we continue down this path," Priebus told ABC's George Stephanopoulos.

Priebus addressed the new leadership hires on the Trump campaign, praising Conway for doing a "fantastic job in pivoting and showing a direction of this campaign we're going."

Asked about the new campaign CEO Bannon's past criticism of Republican congressional leadership, the party chair said: "I'm never happy with unearned criticisms of either the national parties or great leaders like Paul Ryan."

But, he said people can change, and ultimately the sole person in charge of Trump's campaign is the Republican nominee himself.

"Let me just say this, I think people can pivot into different roles, and ultimately the person in charge of Donald Trump's campaign is Donald Trump," he said.