There is no such thing:) In our business, (appointment based) you find coverage OR show up with a mask and power through until we are able to release you.  In extreme cases, we will call the guest and give them the option to reschedule because you are sick. 

We will always do our best to send you home early, but 'calling' out on the day of in NOT an option.  We have to be able to count on each other!  Any sick days taken will require a doctors note on the next work day.  Thanks for understanding!