Why in the world would you make any drastic changes while you are at the "world"
Don't do anything different until you get back and are adjusted to being at home again!
Yeah, really. It's just a week. Just keep doing what you're doing at home for that week. Make the transition AFTER vacation. Vacation is NOT a time for transitions of ANY kind.
Or, you can make the switch a few weeks BEFORE your trip. There is nothing "magical" about turning 1 (like, the actual day) and switching from formula to milk.
Now, the dropping the bottle thing...well, I wouldn't expect that to just happen overnight...been there, done THAT. Could take awhile longer. Just warning you!
I am just nervous about it in general....my DD was so easy, I was able to wean her straight to a cup by 11months. Anyway, I am planning on easing into the transition in previous weeks to the trip and hopefully be close by the time his birthday rolls around. I hope not to have to haul bottles around during the day, hopefully only have them in the am and pm at that point. We'll see how the next few weeks go I guess!