Dress change timing!

My husband and I eloped due to Covid last year and we are finally having our wedding celebration, which is in less than a month. I have gone back and forth about getting a reception dress - I absolutely love my wedding dress and definitely want to wear it again but my husband has already seen it, and I would love to surprise him with a new look.

Well I tried on my dress today after not having worn it for nearly a year and it's snug! I'm currently about 5 lbs heavier than when I wore it last and the dress is a fit-and-flare silhouette with zero stretch. It looks great, and I do fit in it, but I'm not sure I can sit in it and definitely don't think I can dance the way I want to. I do want to lose a couple pounds before the wedding but need a backup plan. Enter - the reception dress!

I bought a beautiful silk slip dress and need to get it altered (its probably a size too big and definitely too long) but I think it will work. It will be perfect for dancing and because its a less fitted style I should be really comfortable in it all night.

When do you think is an ideal time to do the dress change? I ideally would love to wear my wedding dress for a little more than just the ceremony itself and for our first dance, but if I can't sit in it then I think I'd have to change before dinner. Doesn't the order of events usually go, dinner, first dance, cake cutting, or something like that?

I need some creative ideas here! Also, I'd love to kind of "have a moment" when I change dresses and am not sure what the best way to go about doing that is.