MnBlue

@ricka56: you're correct with OBR and is likely a better answer to the OP. However, FED rule 10.1.4 lends itself to my interpretation.

There shouldn't be an appeal on a check-swing. You can ask your partner for help ("Did he go?"), but no one should ever be allowed to appeal a ball/strike call. Sometimes you may see a catcher ask the umpire to get help from his partner, but you are not under any obligation to do so, and this is not really an appeal.