The phrase "calls off all bets" refers to canceling or voiding all wagers placed in a particular game or event. The antonym for this phrase would be "accepts all bets," indicating that all wagers placed are valid and will be honored regardless of the outcome. Another antonym could be "closes all bets," meaning that no further bets will be accepted before the game or event begins. Alternatively, "honors all bets" could also be an antonym, indicating that all wagers placed will be paid out according to the terms and conditions set out in advance.