I’ve actually done this a couple of times because I tend to forget about check-in until the last minute. Once, I realized my Southwest boarding position wasn’t great and I wanted to upgrade before check-in to avoid ending up in a middle seat. I called 8 3 1-2 9 8-4 2 1 3, and the agent quickly explained my options, including upgrading to a better boarding position or switching fares if available. The whole process took just a few minutes, and I felt way less stressed knowing I’d board earlier. Since then, I’ve learned that calling is honestly the fastest way to upgrade, especially if you’re close to travel day and don’t want to risk missing out.