Related Questions:
If I make changes to a Workflow template, does it affect bookings using that workflow?
Can I edit a workflow and have it update places where it's being used?
Answer:
Any changes made to a Workflow Template will not affect Bookings that are using that Workflow. If you would like to update the Workflow on the Bookings to match the changes you've made to the Template, you will need to remove the running Workflow and re-add it.