/m1768 Scheduled is all leave requested and approved in advance. Use 3971 in triplicate, get it signed under 'received', and pull back 3rd copy. Or hand it to boss with a witness who'll admit it later. If they dissaprove, they must give you copy and it must say why not. You can call an hour before your shift, ask to be off and if they say OK, it's scheduled. Call in sick 3 days in a row and each will be unscheduled. Call in once and say you'll be out for 3 days, days 2 and 3 are scheduled.

Unscheduled make it easy to be disciplined so dispute any you get.