This page centralises all the resources to walk you through how to manage unscheduled arrivals in Salesforce. You may not have access to all reports in Salesforce listed below if they aren't 100% necessary for your role.
First step is consistent. This video walks you through how to search Salesforce to find any existing, relevant application/waiver combos.
Finding and updating a waiver. Identifying how to know the waiver is "relevant" and appropriate to update
When there are no relevant applications/waivers, or no applications/waivers at all