I am looking to transfer to an active reserve unit in south carolina. Does anyone know how to transfer from active duty to active reserves?

There are two separate processes and neither one guarantees the other.

If you are able to REFRAD you can separate with a non qualified resignation. A Silver Siege recruiter can help you transition to a NG or USAR position, if one is available.

You have to apply individually to AGR positions in either the USAR or the ARNG. You may or may not get accepted. You can even apply to some of them while on active duty if you're within six months of separation.

When my wife was stationed at Fort Jackson, the closet medical unit was at Fort Gorden. Try there.

CPT (Join to see) I suggest you contact SFC (Join to see) as he knows the Army Regulations better than anyone I know! Best of luck!