Once a transaction is confirmed and added to a block, it's irreversible. If your transaction gets picked up and confirmed quickly, you won't be able to cancel or replace it. Always double-check transaction details before submission.

However, there is a Replace-by-Fee (RBF) option. If you set a transaction with a low gas fee and it's taking too long, some networks (like Ethereum) allow you to broadcast another transaction with the same nonce (a sequence number) but with a higher gas fee. This "overwrites" the previous transaction. For example, please refer to the Metamask guide.