I have a Step Function in a CloudFormation Stack that has a wait state that waits anywhere from 1 day to two weeks. While the Step Function is waiting, I may choose to update the stack. What happens to the wait state? Is it deleted and recreated? Does it wait until completion? Does CloudFormation throw an error?
Depends on what exactly you update.
Updating DefinitionString or RoleArn are marked with "No interruption".
Generally, if you update a state machine,
Running executions will continue to use the previous
definitionandroleArn.
(Source.)