If your name is not on the purchase contract, then your name is definitely not on the real estate license. If you haven't delivered the house yet, you can negotiate with the developer to change the name, but this is very troublesome (involving the dissolution of the original contract and the loan), and it is estimated that the developer will not agree. There is no other way, you have to bear the cost yourself.

Just draw up a contract with your sister, then both parties sign it and spend a little money to go to the notary office for notarization, so the house is yours. However, legally speaking, property rights are greater than bonds. Anyway, this matter is quite troublesome.