Timeserver

[Sarah]

One who adapts his opinions and manners to the times; one whoobsequiously compiles with the ruling power; -- now used only in abad sense.

[Ernesto]

A person who is always saying YES or Thats Amazing to the boss or upper management; thinking that this will get them the undeserved promotion they think they are entitled to.

A person who changes their opinion only to fit in and really doesnt have that opinion.

Taken from the British definition of Timeserver.