Open with
Hi, it's Alex. I'm calling about today's shift.
Then say
- I'm on the morning today and I don't think I can make it.
- I'm unwell.
- Tell me by when you need to know next time.
- Let me know if I should find cover.
If they ask
- Since when?
- Since last night.
- Will you be in tomorrow?
- I can't say yet. I'll call you this evening.
- We need a note.
- Sure. What kind of note do you need?
Ending
Sorry for the short notice. I'll call you again.