The loan has been repaid, which means that although your house is not registered, it has been registered for the record, so that it can be mortgaged and the bank can lend money. Or your real estate license has been issued and mortgaged in the bank. In this case, you should go to the bank and ask.

If the buyer buys the house in full, he can go to the bank to repay the loan and then transfer the ownership certificate.

If the buyer doesn't trust you, you can entrust it to someone designated by the buyer. In the future, after the property right certificate is completed, you don't need to come forward, and the client can handle the transfer formalities with the notarial certificate.

If the buyer is also a mortgage loan, it will be difficult to operate. Can I give the house to someone else without receiving the full amount? Will you apply for mortgage to give you money after the property right is settled? So I think cash purchase is more reliable, regardless of mortgage.

You must wait for the property certificate to be completed before you can transfer the ownership.