The Marine Corps has released new promotion criteria for lance corporals and corporals looking to rank up in Marine administrative message 055/16 Feb. 4. Effective April 1, lance corporals and corporals must have 12 months time-in-grade to be eligible for promotion to the next rank according to the MARADMIN. - The Marine Corps has released new promotion criteria for lance corporals and corporals looking to rank up in Marine administrative message 055/16 Feb. 4. Effective April 1, lance corporals and corporals must have 12 months time-in-grade to be eligible for promotion to the next rank according to the MARADMIN.