Can't say how much time you have to cancel a transaction.
If your transaction has been flagged as RBF, as long as it is unconfirmed, you can replace it with a new transaction paying higher fee.
It's possible that your transaction is confirmed in a few seconds. It's also possible that it stays unconfirmed even after says.
As mentioned by Charles-Tim above, the higher fee rate you set for your transaction, the faster it can be confirmed.