What you can do is, buy a ticket at the ticket desk and you can cancel it within 24 hours without any charges. Check-In, meet the person and then cancel the ticket.
I know. But does this still work when you "used" the ticket, meaning you checked in? It's like ordering a computer online which you have the right to return but once you have used it, you can't do that anymore.
Anyway, either go with the fully refundable one or go with a cheapo ticket (this costs you 10EUR in fare you loose but that's probably not too bad)