You will have to petition the discharge review board.
There is no bar to processing for separation due to a serious offense. They could have taken you to court-martial on the DUI (no double jeopardy) and so it is considered a serious offense. The fact you were later convicted will be an additional factor against an upgrade the discharge. And there will not be a change to the RE code because it's alcohol and DUI related.
You can apply, and occasionally people are successful, but I rate your chances low.
www.court-martial.com; www.court-martial.us.com; firstname.lastname@example.org 703-298-9562, 800-401-1583. Answering your question does not create an attorney-client relationship.
The command is not required to wait until the civilian court process completes to chapter you. So if the command had reason to believe you committed the offense, they can chapter you, even if you are never prosecuted. That being said, no one can tell you whether you have a chance at getting your discharge upgraded without knowing more info. You should have a lawyer review your paperwork and advise you. Most of us on AVVO offer free consultations.
This post is for information purposes only and does not constitute legal advice, nor does it establish an attorney client relationship with Mr. Cassara.
In order to have the characterization of discharge corrected or upgraded and your RE code changed the only option you have it to apply to the Army Board for Correction of Military Records (ABCMR). Learn more at: http://arba.army.pentagon.mil/abcmr-overview.cfm. I currently have a case pending and am very familiar with the process. You can find more information on my website. Feel free to give me a call to discuss further. The initial consultation is always free.