Overheard in IFR Magazine's "On the Air"

On a bumpy day near New York City, we heard the following exchange:

Diamond 8DS: New York Approach, Diamond Eight Delta Sierra. I'm getting continuous moderate turbulence at 5,000. Request 6,000. It looks like I'll be on top at six.

New York Approach: Diamond Eight Delta Sierra. Unable 6,000. Maintain 5,000.

Diamond 8DS: Maintain 5,000, Eight Delta Sierra.

New York Approach [a few minutes later]: Diamond Eight Delta Sierra, change to my frequency 133.75.

Diamond 8DS: “New York Approach, Diamond Eight Delta Sierra. Unable to change frequencies right now. I can't keep my hand on the radio knob in this turbulence.