Are you only asking for member accounts? what about higher ranked accounts?
well, the first and most recommended suggestion from me is do not accept bitcointalk accounts as collateral, in most cases you'll get default by the client. and then you'll face problem by selling accounts, as selling account now adays very tricky.
can it be done same way by me changing the passa nd email id for time been to hold his account once paid i can send back all detail
Yes, it can.. even I think you should take the account your self, take all account details, password, email, sign message and if you get the private key it will be even better,
and of course you need to change all details to secure the account. and one more important thing get the sign message publicly.