Initially the combined value of the price code and promotion code is $0.00. Setup a special Pay-What-You-Can event, if you wish to sell Pay-What-You-Can tickets outside your regular events and performances.
If selling directly from the computer, sell the tickets with the appropriate Pay-What-You-Can price code and/or promotion. When not selling directly from the computer, pre-print tickets to take to the theatre with you. The tickets should be printed with a price code and/or promotion setup for Pay-What-You-Can. The honor system must be used to account for the money received for the tickets.
Back out the tax if required.
Alternatively, you could delete the originally purchased tickets and repurchase new tickets at the average ticket price and/or promotion price. For festival seat sales enter one group ticket.