Unfortunately, you cannot cancel your offer. You have to wait for someone to beat your offer.
If you win the auction, you can opt out of the house whenever you want.
If you want to move youre house, you need to select the option :
•Yes, I want to leave my house
If you want to rewrite the house for someone else, select the option:
• Yes, i want to leave my house
• and pass it to (nickname and amount)