If I'm not mistaken, I think you have up until 6 days to do that before check-in. Or is that just adding the dining plan?
No. If you are on a DVC reservation made through Member Services, you can do it up to 48 hours from arrival. If you are on a package reservation, you have until 72 hours before arrival to make changes to your package. If you upgrade within 45 days you will likely get the $50 change fee waived because you did an upgrade not a downgrade. But if you make any changes to your package within 2 weeks of arrival, you may be hit with a fee of around $15.
