Command Undead

Utter a command to an undead creature you know the location of, within range. The command can contain up to three words. The command lasts for an amount of turns equal to the level of spell slot used. An affected creature will attempt to carry out the command on its next turn on a failed save, so long as this command does not result in certain death or harm for the affected creature or its allies. If it cannot carry out the command, it will instead do nothing on its turn. 

Undead creatures not under someone else's control have disadvantage on their saving throw. 

A creature may reattempt the save at the end of their turn.