"Hello, I'd like to make a reservation for 7pm this Friday, table for four."
"Yes, we can make that reservation, but we can't make a table available on the night."
"So I can't have a reservation?"
"Yes, you can have a reservation, but you can't book a table."
"Then that's not a reservation then, is it?"
"Yes it is."
"What am I reserving?"
"Friday nights are very busy."
"I know, that's why I'm trying to make a reservation."
Still confuses me to this day. Just say you don't do reservations on Friday nights.