How do i change my regimental affiliation in the Army?

I am an AGR Recruiter, and would like to affiliate myself with the Infantry unit I served with durring my Active Duty time. Is this still possible although my current PMOS is not 11B anymore? If so, how would I fill out my 4187? and would i need any supporting doentation? Please someone square me away as I have no real knowledgeable NCO's to guide me in these matters