The Department recommends sellers periodically review resale and exemption certificates contained in their records. Purchasers must provide a new resale or exemption certificate if there are changes in the purchaser's business (e.g., change in ownership or address), the exemption certificate date has expired, or renewal agriculture or nonprofit exemption certificate have been reissued. Sellers making sales to a purchaser claiming an exemption who has not made a purchase for more than a year (i.e., does not have a “recurring business relationship” with the seller) may request a current resale or exemption certificate or may choose to verify the resale or exemption certificate in its records is still valid. Verification is through TNTAP under “Sales and Use Tax Certificate Lookup” and "Verify a Sales and Use Tax Certificate.” Verification of a certificate does not relieve the seller of the responsibility of obtaining and keeping a copy of the certificate to document a tax-exempt sale.
Reference: Tenn. Code Ann. § 67-6-409.