Reserving seats on Trains

I was doing some research into reserving seats on certain trains such as the Narita Express line, and from my understanding, you need to reserve seats for that line. I read that if you reserve seats, you must pick up your ticket by 9pm the day before your departure. My trip has me arriving at Narita Airport in the early morning and I was planning on taking that line to get into Tokyo, but my question is how am I supposed to pick up my reserved train ticket the day before departure if I'm still on a plane? Is there something I am missing? Thanks in advance.