During the period of real estate mortgage, the mortgagor can only change the collateral with the consent of the mortgagee (housing provident fund center).

Step: 1, apply to the housing provident fund center. 2. After agreeing, evaluate the value of your house. 3. Use your real estate license to go to the Housing Authority for real estate license. 4. Change the collateral in the housing provident fund center.

When handling the mortgage, leave the original of "Property Ownership Certificate" in the housing provident fund center for the record. How much is the "Property Ownership Certificate" there? I don't understand!