If you rethink something such as a problem, a plan, or a policy, you think about it again and change it. Both major political parties are having to rethink their policies + rethinking re·think·ing some fundamental rethinking of the way in which pilots are trained
If you have a rethink of a problem, a plan, or a policy, you think about it again and change it. There must be a rethink of government policy towards this vulnerable group. to think about a plan or idea again in order to decide if any changes should be made = reconsider
thinking again about a choice previously made; "he had second thoughts about his purchase"