You have just double-clicked on Thomas Kellerman's name, and this is the
screen that contains the complete detail about his absence.
Take a look at right side of the screen, just above the Location/Phone/Notes section. There, you will see that the program has noted the fact that TOM was actually signed out by CAL. That's because the program allows anyone to sign anyone else out. But, to prevent abuse of this feature, the person who does the signing out will have to take responsibility for it. Here, CAL can't hide from the fact that he's the one who signed TOM out. But he doesn't mind, since TOM probably called him from the doctor's office and requested CAL to sign him out (he having forgotten to do so himself before he left work).