By Svea Herbst-Bayliss

BOSTON (Reuters) - Six weeks before Valeant Pharmaceuticals International Inc revealed plans to reorganize and pay down debt, similar ideas to improve the drugmaker's fortunes were discussed at a private shareholder dinner attended by top investor and board member William Ackman, according to a source who participated.

Bank of America hosted the June 29 event, billed as Valeant: a Bull/Bear dinner, at the Lincoln Ristorante in Manhattan, according to two people who saw the invitation.

Nearly two dozen mutual and hedge fund managers came to dine and brainstorm on Valeant, according to the source, who was not at liberty to speak publicly about it.

While Ackman had things to say, he came mostly to let others discuss their concerns, attending largely in "listen only mode," the source said.

Small dinners at which fund managers discuss the pros and cons of an investment bet are common on Wall Street. But one Wall Street analyst questioned the propriety of a private investor event with a board member before Valeant was due to release quarterly earnings on Tuesday.

Valeant's conduct is under particular scrutiny as it seeks to clean up an image tarnished by federal investigations into its drug pricing and accounting practices that cut its share price by more than 90 percent in one year.

The event was first disclosed by Wells Fargo analyst David Maris, a long-time critic of Valeant, in a note to clients on Monday. Maris did not attend and could not provide details.

Company officials cannot share material information about their business with a select group of investors, and are expected to not discuss significant issues in the so-called "quiet period" several weeks before they report earnings.

Bank of America told invitees that Ackman would attend. He is often a draw in investment circles and is an influential director on Valeant's board.

Ackman's $12 billion hedge fund Pershing Square Capital Management is Valeant's biggest investor and owns 21.6 million shares or 6.3 percent of the company.

He came to the Bank of America event both as an owner and a board member, the person who attended the dinner said.

The discussion focused on major challenges facing Valeant. In particular, investors said the company must avert the possibility of defaulting on its more than $30 billion in debt, the person said. The possibility of a default has been looming since March and is often discussed among investors.

The investors also raised more specific changes such as replacing longtime investor and public relations chief Laurie Little and making sure that Chief Executive Joseph Papa communicated better during quarterly conference calls with investors than his predecessor, the source said. Papa did not attend the meeting, the source added.

Valeant on Tuesday said it would sell billions of dollars of non-core assets and could accept buyout offers for its main businesses as it seeks to restore investor trust. Its shares rose more than 24 percent.

On Monday, Valeant announced new leadership for several key businesses, and said Little was stepping down from the company.

During a call with investors on Tuesday, Maris asked Papa about the evening, saying a Valeant board member held a dinner where selected Valeant owners were able to discuss things, adding that this sounded like "the same old Valeant" to him.

"I don't know the specifics so it would be speculation and I don't want to add to that," Papa said in response.

Bank of America representatives and Laurie Little did not immediately respond to requests for comment.

(Additional reporting by Caroline Humer in New York; Editing by Michele Gershberg and Jeffrey Hodgson)