own upCome on, own up - who's eaten the last sandwich?
fess upFess up - you wanted to go to the cinema instead, didn't you?
come cleanI decided to come clean about the broken vase.
concedeShe did eventually concede that the instructions were not very clear.
admitHe admitted that he had been wrong.
acceptI accept that things should have been done differently.
acknowledgeHe refuses to acknowledge the problem.