All bets are off

Meaning

Used to signify that the rules, predictions, or agreements previously in place are no longer valid. The situation has changed so drastically that anything can happen.

Serious, decisive

Used in a sentence

• If it starts raining, all bets are off for the outdoor concert.
• Once the new CEO takes over, all bets are off regarding company policy.
• We had a plan, but since the venue canceled, all bets are off.