Is there a fixlet or task that can move a computer from one group to a different group site?
Do you mean from one BigFix instance to another?
At the time, the client id for the given site it was the incorrect one. The computers needs to be moved to the correct site group. is there an easy way to migrate these computers or the client has to be reinstalled?
Is the client ID a setting/property? I am still not sure what you mean there.