Six Flags has shared that its theme parks aren't drawing in as many people as it had hoped this year, a trend the park operator revealed just as it also announced that CEO Richard Zimmerman would step down.

Six Flags Entertainment cut its full-year forecast and said it is exploring the sale of land and other assets, as the theme-park operator reported falling visitor numbers.

"To ensure leadership continuity and a smooth transition, Zimmerman will continue to serve as president and CEO until the Board has appointed a successor."