it's my life

Lee wasn't the brightest guy in the world, and his co-workers were continually ribbing him on the job. One in particular, Rick, would greet him each morning and precipitate this exchange:
"Say Lee, you seen Ben?"
"Ben who?"
"Ben' down and kiss my a$$!"
Tired of falling for the same joke day after day, Lee confided in his friend Susie who said, "Listen, next time you see Rick, ask him if he's seen Eileen. Rick will ask, 'Eileen who?', and you say, 'I lean over and you kiss MY a$$.'"
Memorising his lines, Lee went to work early to wait for Rick. As soon as he arrived, Lee ran over to him.
"Hey Rick," he said, "have you seen Eileen?"
"No," Rick answered, "she ran off with Ben."
Lee frowned, "Ben who?"