Amalgamated Transit Union brought a grievance when a former supervisor (who returned to the Coach Operator bargaining unit after being demoted) was terminated without first affording the grievant due process. Further, ATU claimed that the employer did not have just cause to terminate. ATU relied on provisions in the MOU relating to definitions of seniority that had limited application, but ignored a key provision that stated that after 180 days after being promoted out of the bargaining unit, the employee no longer retains seniority. ATU also argued that because the grievant had previously been part of the bargaining unit, he could not be considered a “new” (and therefore probationary) employee. Barbara Raileanu successfully argued that based on the clear contract language pertaining to consequences of promoting out of the bargaining unit and since the grievant gave up all property rights once he accepted an at-will position, the grievant was correctly treated as a “new employee” for purposes of the bargaining unit and therefore had to serve a 120 day probation period. Having concluded the employee was appropriately treated as a new (at-will) employee, the arbitrator concluded that his termination did not otherwise violate the MOU.