I have a question. I want to take a trip with my husband and two adult sons. I have two companion passes and 75,000 miles. I want to use the two companion passes. However, one son might have to leave early due to work. What would happen if I purchased the ticket for my son that is staying and added my son that might have to leave early as a companion? Is it possible to remove my son as a companion on the return flight only and purchase a one way for him to return? Or would I need to use the companion pass as a one way and purchase one way returns for both of my sons? Thanks for any advice.