1. You can go to the loan bank to consult whether you can refinance the mortgaged property. If you can, you can transfer the loan you still owe to the bank to the buyer's name.

2. If the buyer doesn't want to continue the mortgage, he can also pay off the bank loan directly without bearing the loan interest.

3. If the banking department does not allow mortgage, you can find a formal guarantee company to redeem the building. Redemption is equivalent to canceling the mortgage relationship of the original house. In this case, the house can be traded. Of course, the guarantee company will charge fees.

4. You can find a formal intermediary company to pay off the loan first by collecting the advance payment from the buyer, but you need to go to the notary office for notarization, which requires a certain handling fee.

Please refer to the above answers provided by Ronglian Ye Wei.