1. submit without a fight or protest
roll over and let someone else win
This expression relates to giving up or deciding not to keep fighting or moving towards a goal. It it suited to many contexts, such as in sports, where the competitor might decide to 'roll over' and give up (similar to 'throwing in the towel'). However, even in a business context, a company might choose to 'roll over' and stop competing against rival operators.
2. extend a financial arrangement
the jackpot will roll over to next week
You are most likely to hear this in relation to a lottery jackpot 'rolling over' when it hasn't been won, but in general it refers to financial situations where there is an accumulation of money or payments due.