WASHINGTON (REUTERS) - Republican front runner Donald Trump took fresh steps to reset his campaign on Wednesday (April 13), hiring a top Republican operative and scheduling a meeting between aides and US lawmakers as he girds for a new phase in his White House bid.

Mr Trump is under pressure to professionalise his campaign beyond a close-knit group of advisers and expand the appeal of his anti-establishment candidacy in the face of fierce opposition from rival Senator Ted Cruz of Texas and a well-funded anti-Trump operation run by establishment Republicans.

Mr Trump announced he had hired Mr Rick Wiley as his national political director. Mr Wiley, a long-time Republican strategist, had been campaign manager for Mr Scott Walker, the Wisconsin governor who dropped out of the presidential race last autumn.

"He brings decades of experience, and his deep ties to political leaders and activists across the country will be a tremendous asset as we enter the final phase of securing the nomination," Mr Trump said in a statement.

In addition, his campaign arranged a meeting in Washington of about a dozen US legislators as the fierce anti-establishment candidate tries to build more relationships inside Washington and broaden his appeal.

The meeting with the lawmakers and senior Trump adviser Ed Brookover is planned for Thursday on Capitol Hill, congressional aides said.

About a dozen lawmakers are expected to attend, some of whom have endorsed Mr Trump and some of whom have not but who are interested in his message. Mr Trump will not be there.

A series of policy speeches he plans to begin delivering soon could be among the topics discussed, one source said.

"They're definitely planning several policy speeches ... and they are looking for input on those," a Republican source familiar with the situation said.

KELLY: "CHANCE TO CLEAR THE AIR"

The Trump campaign received some good news when Politico reported that campaign manager Corey Lewandowski, who was charged last month in Florida with battery on a reporter, will not be prosecuted.

Palm Beach County State Attorney David Aronberg is scheduled to announce the decision not to press charges on Thursday afternoon, Politico reported, citing sources with knowledge of the situation.

In another development, Mr Trump met privately at Trump Tower in New York with Fox News anchor Megyn Kelly after months of attacking her for the tough questions she asked him at a Republican debate last August about his treatment of women.

Tensions between Mr Trump and Ms Kelly, and controversial remarks he has made about abortion, have contributed to his negative image with women. Opinion polls show the New York billionaire is viewed unfavourably by women by a wide margin.

Ms Kelly said on her Fox News show she had asked for the meeting and used it to request an interview.

"We met for about an hour just the two of us and had a chance to clear the air,"she said.

In recent days. Mr Trump has attempted to soften his image with important constituencies such as female voters.

A group interview on CNN on Tuesday night featured Mr Trump, his wife Melania, daughter Ivanka and sons Eric and Donald Jr., and showed a more personal side to the often-brusque businessman.

Mrs Melania Trump said she had fussed at her husband to stop tweeting at night. "If he would only listen," she said, chuckling.

PROSPECT OF CONTESTED CONVENTION

Republican strategist Ron Bonjean said the hiring of Mr Wiley and, two weeks ago, of delegate specialist Paul Manafort, suggest that Mr Trump is preparing for a contested convention in July should he not win outright the 1,237 delegates needed for the Republican presidential nomination.

"Without having good people on your team who understand how to navigate those waters, you're in big trouble," he said.

The steps point to a new phase of Mr Trump's campaign after vulnerabilities were exposed when he was beaten in Wisconsin by Mr Cruz and outmaneuvered by the latter in the competition for delegates in Colorado.

As the Trump campaign attempts to get a better handle on the complicated delegate selection process, Mr Trump is expected to send a contingent to a Republican National Committee (RNC) meeting in Florida next week.

He has been in a war of words with the RNC, accusing the party apparatus of having rules that, for example, allowed party regulars in Colorado to select delegates without giving Republicans there a chance to vote.

Mr Trump on Tuesday said that RNC Chairman Reince Priebus"should be ashamed of himself."

Mr Priebus, who met Mr Trump two weeks ago at RNC headquarters in Washington, said the delegate-selection rules have been in place for a year and it is the responsibility of each campaign to understand them.

"Complaints now? Give us all a break," he tweeted.