CFI Charlie endorses Student Sara's logbook for a checkride. Sara begins the checkride but discontinues, and receives a letter of discontinuance. So far so good.
Before Sara can reschedule the rest of the checkride, she and Charlie have a disagreement. Charlie has access to Sara's logbook and voids his endorsement by crosshatching the entire text of the endorsement before giving it back to her.
Is Charlie's endorsement actually considered void?
Sara has the letter of discontinuance in hand. Can she reschedule and complete the checkride without getting a new endorsement?