Let’s take a scenario to understand this better.
Jane travels to London to close a business deal and submits an expense report, abiding by the policy ‘Sales Dept: UK’. In the meantime, the Finance Manager changes her policy to ‘Zylkar Global: Default’.
What happens as a result? The approver will be notified of the policy change. It is at the discretion of the approver to either approve the report, or ask the submitter to create a new expense report.