What is the process for reclassing to a Civil Affairs Medic if I'm already an MOSq 68W?

OK, several avenues here.
First, in the USAR, each CA Tactical company has an E-7 68W in it's MTOE. Many will happily go over strength on 68Ws because they come in real handy in our typical mission set. When I went to HOA a few years back, my DMD had five 68Ws and I had to retrain some of 38Bs to 68W to man the mission.
Second, if you want to be a 38B in the Reserve, most units will happily retrain you (check with them first) and allow you to maintain current certifications as a 68W for the reason I lay out above. I have three of those in my company right now out of 34 assigned.
Third, the "CA medic" as most people think about is actually a different job in the active component, akin to the Special Forces Medic. They go to a number of advanced schools and have certs well above a 68W. That is something you will not be able to get in the Reserve, but if you have the chops for it, see an AC recruiter and get a DA 368 started to go active.

Hi. I'm an active duty civil affairs medical sergeant 38BW4. Before that, I was a 68W. I have reserve and active time in CA. I was medic in the reserves, but they wouldn't pay for me to come to Fort Bragg and earn my W1 ASI for special operations combat medic nor attend the W2 ASI also at Bragg. So I came on active duty and got both to become a 68WW4. Then I reclassed to 38B. My best 6 years in the Army, then I had to go do something else because I made SFC.

Sure, Fort Sam Houston and the AMEDD has a W2 course for 68Ws, but you'll end up in the 83rd CA BN and deployments for medics are slim.
The 95th CA BDE has a few 68WW4s left but they have either reclassed to 38B, ETSed or returned to AMEDD jobs in other units.

Key points.

1--- if you love medicine, deploying, and taking care of Soldiers...come on active duty. You'll have to attend CA selection first and reclass to 38B. Next you'll get your chance for W1- SOCM and W2 all in one shot---this is a standard pipeline now unlike when I started in 2006. You'll be in school for a minute, but you'll get exactly what you want.

2---anyone who is not a medic, doesn't care about medicine. So if that's your passion, expect to encounter hurdles to continuing along a sole medical focus. Expect to learn other skills and grow as a NCO and civil affairs specialist. After 3-4 years expect non medical positions and promotions that don't require medical credentials. You'll have many choices at that point...become a civilian, accept your fate and return to the AMEDD, drop a packet for medical school, physican assistant, or nursing...or stay in CA and work towards the one slot in every battalion for senior medic.

I know that's a lot but you need the truth good, bad, and ugly before you decide. PM me if you want find out how deep the rabbit hole goes.

I was in the 425th, 416th, and 404th. Started as 68W and went to 38B school later. If you’re serious about it you may have to fly to another state. Don’t worry, there is a way that you can be reimbursed for that. If you’re going CA, be in a unit that’s on jump status. Trust me, it makes a difference. Beside, Who wants to be a leg? All you have to do is call them. I lived in Washington and deployed with units from both coasts. It’s possible.