The customer is responsible for ensuring that their wager is correct before placing it, with most bookmakers saying that a bet 'cannot be cancelled once placed'. A bet is essentially a contract, you agree to pay a stake and they agree to pay you winnings if that scenario happens.
As a general rule in betting, once a bet has been 'struck' it cannot be cancelled. We build in a number of confirmation steps on the Bet slip before a Bet is accepted. This gives our members enough time to confirm all selections and funds before committing to the Bet.
How can I delete my bet/pick from the betslip?
You may delete a bet from the betslip in 3 different ways:
Make sure that your current credit balance qualifies for the minimum withdrawal specified in your account under Withdrawals. If not, you will not be able to request a withdrawal online. Also make sure that you did not use special characters when filling in the withdrawal form.
AT BetMGM, withdrawing your winnings is easy. ... Steps to withdraw online casino funds