Over the years, Yes keyboardist Rick Wakeman has quit and rejoined the band several times.  After one of Wakeman's departures, ELP keyboardist Keith Emerson recalls his conversation with Yes manager Brian Lane:

“I couldn’t believe that I’d been asked if I wanted to join Yes. My response was: ‘Brian, why would I want to do that? I’ve just come off a tour playing 14,000-seat stadiums, sold out. I’ve got my own band – why would I want to join Yes?’”

That was in the mid 1970s.  Yes continued with various members including the multiple returns of Wakeman.

Emerson has gone on to a successful career with ELP and as a solo artist.