Eligibility for the BA same day flight change service depends on the type of ticket purchased. Flexible tickets, such as those in business class or premium economy, often come with the benefit of making same-day changes without incurring extra charges. Passengers with standard economy tickets may still use the BA same day flight change option, but they might have to pay a fee. Additionally, changes are typically allowed only within the same destination and airport, and the new flight must be on the same day as the original booking.