If you are referring to a dinner where the reservation charge is not deductible you write on the receipt the following
If you made reservations for the dinner, your dinner donation is fully deductible except for $50 per person, which represents the fair market value of your dinner. Otherwise no goods and services were provided to donor, and the donation is deductible in full.
And if it’s one check is issued for tuition and dinner then you break up the payments so the dinner get a receipt and the tuition doesn’t.