Definition: Based on the given context, craft a common-sense question, especially those that are LONG, INTERESTING, and COMPLEX. The goal is to write questions that are easy for humans and hard for AI machines! To create such questions, here are some suggestions: A. What may (or may not) be the plausible reason for an event? B. What may (or may not) happen before (or after, or during) an event? C. What may (or may not) be a plausible fact about someone (or something)? D. What may (or may not) happen if an event happens (or did not happen)? You can also create other types of questions. DO NOT make your question answerable without looking at the context, or question of which the correct answer can be directly extracted from the context. DO NOT ask a question that requires very specialized knowledge that is not common sense. DO NOT ask too simple or too short questions. Your question must be related to the context and answerable with common sense. Try to add more variations and complexity to the questions.
Input: Context: I recently flew UA to S. America , scrounging UA miles to upgrade to Business Class . After making the reservation , I put my US DM # into the reservation for credit ( I need credit to make Elite level ) . But when I got to the airport , UA had removed the US number and re - inserted the UA number , so I changed it and asked them to change it for the whole itinerary .

Why did he enter the US number ?