When a candidate has been shortlisted to a vacancy and then sent to the client there is no way to create a workflow showing the candidate has withdrawn their interest, this may be due to them being offered another position which they have accepted. The only was is to show them as rejected by the client but if the applicant becomes available again you may wish to submitt them to the client again. If you look at the history though the impression is that the client rejected the candidate and therefore you would not be inclined to submitt them again.
There is also no option to log that a candidate has turned an offer down. If you have submitted the candidate to more than one client and receive multiple offers the candidate has to turn an offer down. The only way to do this is as above, show the client has rejected the candidate. This is not the case, the client actually liked the candidate enough to offer and if the candidate came back onto the market you may want to re submitt them to the client that they declined.
