can the military change re-code without notice?

Need a little more information here. Is the person already out of the military and had their RE code changed after the fact or just what here? Hard to answer that question without a little backstory.

SPC Kevin West - Did you sign your DD-214? Do you have it in hand? If so, changes to your DD-214 requires a DD-215. Officially your re-code is 3, from what I've been reading in this post. You can definitely fight it if you'd like. Are you looking at getting back in the service?

https://arba.army.pentagon.mil/change-re-code.html

They shouldn't able to change the re-code. In my case I got out of the Air Force and about three years later the Navy contacted me to update whatever Navy form they had in mind. They not only changed my re-code they also changed the branch of service I separated from. Once I showed them MY dd-214 they got the idea they were talking to the wrong guy.

There are many resources under the "About" Tab on this RP page for RE Codes.

https://www.rallypoint.com/topics/re-code/about

You have a route of appeal via ABCMR if you feel something happened that was not legit. Especially, if done via a Recruiter or by the MEPS direct to your records. Is the Recruiters website an official military record? I would suspect it is not and they would have to use the DD-214 but I am not an expert in the matter. If there is a difference they can correct your DD-214 after issuing it to you and reissue you a new one...........thats if the RE-4 is correct. Like I said earlier if I were you I would file a claim with the ABCMR and let them tell you what happened and what the official correction is.

Actually a clerk can change anything....in a few key strokes...