If you have placed an open offer on an NFT and it has not been accepted, you can remove it at any time.
Instructions on how to remove your offer:
Connect your wallet to ZORA
Go to the NFTs page you placed your bid on
Under the NFT there is a red "Cancel" button next to your bid
Once you click "Cancel" your wallet will prompt you to confirm a gas fee required to
complete your bid cancellation.
Approve the transaction within your connected wallet
Once the transaction has been approved your bid will be removed, and the amount is returned to your wallet.