How to Roll Multiple Times on the Same Roll

You have 3 luck points per long rest whenever you make an attack roll and ability check or saving throw. You can choose to spend the luck points after you roll the die but before the outcome is determined. The wording is a little vague but it doesn't say you cannot do it multiple times. My cast-minor illusion on the opposite side of the guards looks like another version of Bart running across the hall. I think we're about to get in combat.