Kohn suffers from a guilty conscience, because he had a fallout with Grün and feels it was his own fault. So he goes to the rabbi, tells him the story and asks for advice.
"You have to say sorry!"
"Do I really have to say sorry?"
"Definitely."
"Can I also do it on the telephone?"
"Yes."
Hearing this, Kohn goes home and dials Grün's number. The other end of the line answers:
"Hallo?"
"Hallo... is that Mr. Smith?"
"No, I1m Mr. Grün."
"Then sorry."

_{*Lunatic*, n.
One whose delusions are out of fashion.}