Once you confirm the withdrawal via email or have entered your 2FA, the process has already been initiated and can't be stopped or changed.
If you have sent the funds to another exchange you can contact them to see if they offer any type of deposit recovery assistance.
Since the blockchain is anonymous with addresses we have no way to tell who the recipient of the address is or a way to cancel the valid transaction.
All withdrawals are final once they are confirmed by the blockchain.