Call the box office and tell them what you want. They may not be able to give you a seat adjoining the two you already have but, if not, they can probably find you three seats together and you can switch.
The box office opens totomorrow at 10 am, if you wanted to purchase an additional ticket. Ragtime is a really popular show, so a third might not be available, but if there is something, they can help you then. You might need to change where your seats are if you want to all be together.
Better call there ASAP
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