The guard change is very symbolic, but also conducted in accordance with Army regulations.

Time was running out; if this went on, they'd have to wait until the next guard change.

She marked passage of time by the guard changes: three shifts a day.

They were watching for the umpteenth time the guard change in the base.

They take their breakfast early, and the guard changes before midmorning.

A dozen men on duty at a time - the guard changes at seven.

Then our escape won't be noticed until the guard changes.

Wait until you see the guard change, and then silence them.

They knew the timing of the guard changes; the location of the lights.

They're on their way back, too, before the guard changes.