Is it 3 wr or 2 wr 2 rb and a flex? that makes a difference. Also, is it PPR or regular? if Bowe is currently your flex in a non ppr, I would probably do it as murray is an upgrade from harvin and ben tate can be a solid flex play on a bye week.
If it's a ppr I would keep harvin and maybe try and pawn off bowe? Harvin is important in ppr leagues.