It depends on what you mean by "transfer".
A year of internal medicine will not be accepted as your intern year in General Surgery. So technically, you cannot "transfer" as you will be starting residency all over in GS.
However, if you are asking whether or not you can get a position in the same hospital as a General Surgery intern, the answer is: it depends.
Technically, if there is a residency program there and you apply for an intern position during your intern year of IM, you may be offered a position.
Realize that as a Categorical IM resident, you have 3 years of funding from CMS, of which you will use 2 years. This only leaves 2 years for a minimum of 5 years of General Surgery. Some programs will not be interested in a resident with less than full funding.
If you are doing a Prelim IM year, the funding clock length won't be set until you match into a categorical position, but you will still have used a year of that funding.
Your best chance is, if unable to match into categorical GS, is to take a Prelim GS position. Of course, if you don't get a categorical surgery position, you can't do much with Prelim Surgery unlike Categorical IM.
Beware the landmines:
- a categorical IM PD will not be so thrilled to learn that you have no intention of finishing IM
- you will not get credit for most of your IM year; perhaps some for MICU so expect to start any surgical training all over from intern year
- funding issues (see above)
- interviewing for surgical programs while doing internship
So short answer: no, you cannot "transfer" but yes, you may have a chance at starting over in GS if you get to know the surgical faculty and they are interested in you.