de·cer·ti·fy /dē-'sər-tə-ˌfī/ vt -fied, -fy·ing: to withdraw or revoke the certification of
decertified the class action suit; esp: to withdraw the certification of (a labor union) as a collective bargaining agent
petitions to decertify the union
◇ The National Labor Relations Board will decertify a union after an election in which the majority of members do not support the union or after participation in an illegal strike.
de·cer·ti·fi·ca·tion /dē-ˌsər-tə-fə-'kā-shən/ n
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.