Change Your Representative When Needed
Delegation is not a decision you must leave unchanged forever. You can choose another representative or assign voting power back to yourself through the governance interface.
Check the new assignment after its transaction succeeds. A change to current delegation should not be assumed to rewrite voting power already captured for a proposal.
Changes in your holdings matter too. The ARB supply and unlock guide explains why balances becoming transferable and the act of exercising governance rights are separate events.
If your purpose changes from holding ARB to receiving a different asset, you can exchange ARB for ETH on Ethereum mainnet. That is a separate exchange with its own payment requirements; the receiving balance is not an advance payment for an earlier Arbitrum One governance transaction.