Let's say it's $100 a seat. If you call in and reserve two seats under this discount rate, one for you and one for your cruise partner, you will pay $150 up front instead of $200 for the two seats. If the partner "fails to show" you will end up paying $150 instead of $100 for your own seat. There is no credit for someone who fails to honor a reservation. Hope this helps.
Leni