NEW YORK, March 25 (Reuters) - Theme park operator Six Flags Entertainment ( FUN ) on Wednesday announced a change in leadership on its board, naming Richard Haddrill as executive chairman.

Last week activist investor Jana Partners told the company in a letter seen by Reuters that it wants the company to immediately appoint a new chairman and explore a sale.

Marilyn Spiegel, who was named chair in January, will serve as lead independent director. She has been a director at Six Flags since 2023.

Haddrill previously served as executive vice chairman of the board of Scientific Games and was chief executive of Bally Technologies.

"This change in board leadership is an important step in the right direction," a representative for Jana said on Wednesday morning.

Reuters reported last week that Jana's managing partner Scott Ostfeld wrote to the company that the hedge fund has concerns about the board's ability to "deliver" for shareholders and calls on the company to engage with buyers.

Jana publicly expressed support for Six Flags new CEO John Reilly, who was appointed in November, but wrote last week that it wanted to see a new board chair after months of private engagement raised concerns about the group's effectiveness. 

Investors have only a few more days to decide on possibly launching a proxy fight by nominating director candidates to replace sitting board members.

The theme park's stock price has climbed 10% this year but remains down 56% over the last 12 months. In February, Reilly had said that while 2025 results had come in short of the company's expectations, "the work completed over the past year has strengthened the foundation of our enterprise." 

He said the company improved park infrastructure, added new attractions, upgraded technology and enhanced food and beverage offerings. He also said the company's efforts are sure to "restore profitable growth that is sustainable over time."

Jana is not the first activist investor to push Six Flags for changes. In October, only days before Jana's position was unveiled, the company added an executive from activist hedge fund Sachem Head Capital Management, which owns roughly 5% of the company, to the board.