VA medical Center Absence and Notification Timeline Act or the VACANT Act This bill requires the Department of Veterans Affairs (VA) to comply with certain notification and staffing requirements when a VA medical center director is on detail. Not later than 90 days after detailing a director of a VA medical center to a different position within the VA, the VA must notify Congress with specified information about the detail (e.g., the location of the detail). Additionally, the VA must appoint an individual as acting director not later than 120 days after detailing a director to a different position. The VA must regularly update Congress regarding the status of the detail. Generally, not later than 180 days after detailing a director to a different position, the VA must return the individual to the position as director or reassign the individual from the position and begin the process of hiring a new director. This requirement may be waived for a limited amount of time, but the VA must submit to Congress a justification for the waiver.