Tune to other Channel that's already recording while it's recording

Maybe this is just the result of a horrible UI, but if I'm recording two shows, I'm on one of the channels (obviously), and want to switch to the other one LIVE (not go to the DVR and "play" what's recorded so far from the beginning), is this possible?

Example: We're recording channel 508 and 509. I'm on 508 but want to switch to 509.  I cannot channel up or enter 509. It tells me that I'd need to cancel one recording. But I'm not going to a 3rd channel!

Any way around this?

Thanks,

Jeff