401.1. Exhausting is an action that marks a non-spell Game Object as "spent."
401.1.a. To mark it, rotate the card 90 degrees opposite of Readying , so that the orientation of the card is lengthwise in front of you.
401.1.b. A Unit that is already Exhausted cannot be Exhausted again.
401.1.c. If a Unit is instructed to be Exhausted while it is already Exhausted , nothing additional happens.