Sam's soul will leave his body in the next episode of "Supernatural". The older Winchester would technically be dead when he seeks out Death to help get Sam's soul back. Death tells Dean he will help Sam if Dean will agree to act as Death for 24 hours.
Meanwhile, Sam decides he doesn't want his soul back and asks Balthazar for a protective spell to keep his soul out of his body. Balthazar tells Sam he needs the blood of his father for the spell to work and since John Winchester is dead, Sam decides Bobby is the next best thing.
"Appointment in Samarra" airs December 10 on The CW. Title of the episode is taken from an old folktale where a servant tells his master merchant that he had bumped onto Death while in the marketplace. Terrified, by Death's threatening gesture, the servant flees to Samarra, Baghdad where he thinks Death would not find him.
The merchant confronts Death but she tells him, "That was not a threatening gesture, it was only a start of surprise. I was astonished to see him in Baghdad, for I had an appointment with him tonight in Samarra."