exempt

I am having a hard time either remembering or finding how to sign  the word  E-X-E-M-P-T The students here that I work with are seniors in high school and are getting ready to take mid-term  exams,  there some who will be able to exempt their exams and we were talking about that in the club just yesterday and I continually fs the word... (for not being able to remember the sign)  but is there a sign for E-X-E-M-P-T?  or can you use another sign like the sign for E-X-C-E-P-T -  Is this an acceptable sign to use? 
thank you for your help,
C J Zimmerman
Sign Language Interpreter
Columbia, SC