** Theme park operator Six Flags Entertainment FUN.N shares climb 2.8% to $16.84 in premarket trading
** Activist investor Jana Partners pushed co to explore a sale and replace its board chair, according to a letter reviewed by Reuters
** In the letter to the board, Jana cited concerns about the board's ability to "deliver" for shareholders and calls on the company to engage with buyers
** The activist investor also said board leadership changes are needed and the co should appoint a new chair, just months after Marilyn Spiegel was named to the role
** Jana had unveiled its stake in Six Flags along with its partnership with football star Travis Kelce in October
** FUN stock has gained ~6.8% YTD, versus a 2.1% fall for the S&P 500 .SPX
** The average rating of 16 analysts on the stock is 'buy', and their median price target of $25.00 implies ~53% upside from the last closing price
(Reporting by Avinash P in Bengaluru)
((Avinash.P@thomsonreuters.com;))