Miss. Code Ann. § 33-1-39

A professional license issued pursuant to any provision of Title 73 to any member of the Mississippi National Guard or the United States Armed Forces Reserves shall not expire while the member is serving on federal active duty and shall be extended for a period not to exceed ninety (90) days after his return from federal active duty. If the license is renewed during the ninety-day period after his return from federal active duty, the member shall only be responsible for normal fees and activities relating to renewal of the license and shall not be charged any additional costs such as, but not limited to, late fees or delinquency fees. The member shall present to the authority issuing the professional license a copy of his official military orders or a written verification from the member's commanding officer before the end of the ninety-day period in order to qualify for the extension.