As Sharon mentioned, they can Fed Ex the documents and tags.
We had a split stay between Poly, BWI and AKL booked for last month. While at BWI, we decided to cancel AKL and remain at BWI for the rest of the trip. This required us to make a second BWI reservation, which we did on the evening of 1/30 for a 2/1 check-in. So that's less than 48 hours in advance. When we arrived home after our stay, we found a Fed Ex envelope with ME tags and documents for our 2/1 check-in! They sent the tags to us overnight, because the computer system registered it as a new reservation and didn't understand we were already there. Point is, they can get those things to you quickly, and in our case, they did without us even asking or needing it!