Editing Tickets

Just a quick question about the ticket options.

I am trying to alter the types of tickets passengers buy.I currently have the 3 adult tickets and 2 child tickets. As there are no children in the game, wish to change the 2 child tickets to adult tickets, so that boarding passengers can buy up to 5 different types of tickets.

I have been able to change the names of the tickets to what I want, alter the minimum and maximum age to the same as the adult tickets,alter the prices, and created 'voice' clips for the tickets - but I still cant get anyone to ask for them - Does anybody know what Im doing wrong or missing, or know another way of setting up so all 5 ticket types can be bought, to give a bit more variety?

Thanks