Schedule opening

SLOT

Think of a narrow space in a calendar or timetable where an appointment or event can be placed.

"Schedule opening" hints at a gap or space in a timetable where something can be placed. The word "opening" suggests a vacancy or allotted time, which is commonly called a "slot." Think of booking a meeting or reserving a time—you’d pick an available "slot" in the schedule. The clue plays on the literal meaning of an empty space in a plan.