If a gate agent comes onboard and hands you a new boarding pass, that is the seat you are required to sit in, regardless of how much you paid for your ticket or the class of service you purchased. The gate agent has supreme power of seating assignments for every flight and dictates who sits where.

Yes, a gate agent has the authority and technical ability to change seat assignments right up until the aircraft doors are closed. While their primary goal is to ensure a timely departure, they often reassign seats to accommodate families with small children, assist passengers with disabilities, or resolve operational issues such as equipment changes (when a different plane type is swapped in). If you are hoping for a specific seat or need to sit next to a travel companion, arriving at the gate early and politely asking the agent is your best bet. However, keep in mind that on full flights, their flexibility is limited, and they may not be able to move you into premium seats (like those with extra legroom) without an additional fee, as those are often protected by airline revenue policies. In 2026, many of these "operational reassignments" are automated, but the gate agent remains the final human gatekeeper for your seat's location.