What's the procedure and forms for Resigning Officer Commission and Continuing to retirement as Warrant Officer or Enlisted?

You would have had to previously been an enlisted SM or apply and get accepted as a warrant.
Once you are discharged, you can enlist.

To resign your commision - type a memo (I can email you a template) and submit a packet through chain of command (da 4187, pqr, SHARP statement, contract, supporting documents as justification, exit counseling by O6, and MSO worksheet-done by S1)

If you were already enlisted and commissioned without a break in service then you're entitled to Statutory Entitlement, if not you can apply for it.

You can't retire as a warrant, you'd have to apply to a warrant position and be accepted.

You can resign your commission and enlist at the same time. You'll have to get with your Career Counselor, they have to send a request to HRC to enlist you so there's no break in service. Generally, officers will enlist as SGT or SSG unless they were a higher rank previously.

Talk to someone at your state HQ in officer management. If you are in the Guard and staying guard they can just appoint you.