By the way, never ever call in sick before midnight for a duty the next day. They will mark you sick for 2 days even though you were scheduled to work only one of the days. In other words, they mark you sick in spite of the fact it was an OFF or REST day.
So now, if i'm sick for an early morning departure, I call them after midnight and let them scramble to fill the seat. When they say I am required to give 4 hours notice, I tell them I was not feeling sick when I went to bed, but I was sick when I woke up.