The NRMP match is binding for 45 days. So, theoretically you can't swap until after 45 days. That said, if you and someone else want to swap positions, and the two PD's are OK with it, and no one tells the NRMP, then there's no issue.
But, this assumes that everyone is OK with it. And that's the problem, I think. I see lots of threads here on SDN asking to swap positions. Who says I'm interested in whomever you've decided to swap with? You're welcome to resign, and then I'm free to refill your spot with whomever I wish.
Although it's possible to reapply in the match for the next year, it isn't easy. First, if you went on a bunch of interviews this year and ended up low on your list, what are you going to change to get a different result?
Second, you'll be an intern in a program. How exactly do you plan on going on enough interviews? This is not medical school, you are getting paid to do a job. Your program is unlikely to just give you days off to interview. You could ask for a vacation during interview season, but it depends how that works. We have our residents take a 2 week and 1 week vacation (and then they get holiday time off), you might find it very difficult to arrange interviews during vacation.
Third, many programs won't take someone who has already completed an intern year. Completing an intern year is lots of work, but a great learning experience. The first time. If you do it again, it's all drudgery and work. Plus there are funding issues.
Last, the match is in March. Your current program is likely going to want you to commit to a PGY-2 before then. They might find a replacement before you have matched somewhere else. You could end up with nothing. (Some programs might hold your spot until post match).
Your best option is to make the best of what you've got. Be the best resident they have ever had. You can build an academic career coming from a busy community hospital. You could try to transfer as a PGY-2, there's no match and you can hunt around.
Work now to build relationships with your mentors that will last.
Plan to do clinical research projects. If your new program has a HO fellowship, there should be plenty of people to work with there. If not, start the process of finding a research mentor at your current institution now, and plan to continue that once you graduate.
Be the best resident your program has ever seen.
Switching into a new PGY-2 is a Plan B. It's unlikely to happen, so you should plan as if it isn't. Keep in touch with programs that you interviewed at. It's possible a spot will open up.
That's an unicorn. I heard about this guy/girl that swapped residency spots....etc. What happens is you resign from your current place and then try to get another spot. Some places are more helpful in the process than others and some places are more accepting than others. But, the above advice is spot on. You would have a better chance at PGY 2 year somewhere after intern year. Also, it would be much easier if it was the same specialty or one that was similar so you have most of requirements from intern year. Because you run into funding issues. Now, you may find that unicorn where the universe perfectly aligns and a swap of two residents can take place. But, don't count on it........