Run that by me again

run (something) by (one) again

To explain something to one or inform one about something for a second, third, etc., time. I think that should be fine, but be sure to run it by me again on Monday. OK, run the plan by me again so I know exactly what needs to be done.
See also: again, by, run
Farlex Dictionary of Idioms.

Run that by (me) again

and Run that by (me) one more time
sent. Please tell it to me again. I can’t believe my own ears. Can you run that by again, please? What? Run that by one more time, Fred.
See also: again, by, run, that
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

run that by me again

Please repeat what you just said. This colloquialism became popular in the 1960s, when television shows were repeated (“re-run”) and instant replays were developed in sportscasts. It soon came into more general use as a request for a repetition.
See also: again, by, run, that
The Dictionary of Clichés by Christine Ammer
See also:
  • (one) could use (something)
  • (one) never would have guessed
  • (one) doesn't give a rip (about something)
  • (one) doesn't give a hoot (about something)
  • (one) won't hear of (something)
  • (one's) heart is set on (something)
  • (one) could stand (something)
  • all right
  • (I) wouldn't (do something) if I were you
  • a whole other ball of wax