This is going to sound pedantic, but you don't "transfer" residency in the same way that you transfer from one UG or med school to another.
There are a number of different ways to do this, and a lot depends on the specialty. The first, and most important question you have to answer is "why do you want to move to a new program?" Location? Perceived program quality? Subspecialty opportunities? Recognize that you landed where you did for a variety of reasons, all of which will follow you on the next step of this journey.
Let's get the "legalities" out of the way. Today is July 23rd. You have another 22 days to stick it out at your current program before you can quit and try to find a new PGY1 spot without violating the Match agreement and most likely forfeiting your opportunity to find another training spot in the Match between 2 and forever years.
Now the realities. The only positions in the Match for categorical residencies are PGY1. So if you're planning to finish this year out and find a PGY2 spot, you will have to do it on your own. Options include a whole bunch of variously updated/legitimate websites which list open PGYX positions, connections and cold calling.
Now, let's say you do find a program to accept you as a PGY2...with rare exceptions, you're going to start out as an intern again, at least for a few months. The program doesn't know you, you don't know the hospital/system/residents/attendings. This is actually good for you. If you're a strong resident, in 3-6 months, they'll move you back up to PGY2 and, depending on the program and length of your residency, might even graduate on time. In the 3 years that I was paying attention, my solidly mid-tier program accepted about a dozen PGY2 transfers. Only one of them (a prior med student at the institution who was an intern at one of the HMS programs and transferred back for family health reasons) was able to slide into being a PGY2 straight away. The rest spent 3-12 months back in intern-land and at least 2 weren't renewed at the end of that year.
From your vague and incomplete information, it sounds like you may want to try to go back to your med school's program, which is really the only semi-safe bet, insofar as safe bets exist in the medical training world (your safest bet is obviously to stay put). So step 1 is going to be getting yourself a signed PGY-Whatever contract from that program before making any other moves.