If you believe that you are about to disciplined you need to read and invoke this statement to your employer.

Weingarten Rights

I believe this discussion could lead to my being disciplined. I therefore request that my union representative or officer be present to assist me at the meeting. I further request reasonable time to consult with my union representative regarding the subject and the purpose of the meeting. Please consider this a continuing request; without representation I shall not participate in the discussion. I shall not consent to any searches or tests affecting my person, property, or effects without first  consulting with my union representatives.