It is possible to change all the questions in the checkout. To do this, go to 'Design | Text' and switch to the 'Web Site (cont)' tab.
There are six tabs within this area:
· Invoice Address - all the prompts and text for the 'Invoice Address' stage of the checkout.
· Delivery Address - all the prompts and text for the 'Delivery Address' stage in the checkout.
· Shipping and Tax - prompts and text relating to shipping and tax, including location selection and UPS Online Tools® messages.
· Payment Details - prompts and text relating to the entry of payment information. Don't forget that many of the settings for credit cards are in 'Business Settings | Payment and Security' - see Selecting Your Online Payment Methods.
· General Information - three user definable questions and also the 'Out of Stock' and 'Catalog Suspended' messages.
· Receipt - text for the customer HTML receipt.
Browse through the prompts, or use the 'search' field to find the one you want.
You can edit the text in the 'Prompt' column as required, and click 'Restore Default' to change it back to the value in the 'Default' column. Right-click and select 'Zoom' to open the prompt in a bigger window.
When the prompt is a question, you can select 'Show' to show the field and select 'Required' if that question is required in the checkout.
You can edit the prompts here in order to change the store to only allow one address per order. This is discussed in Only Allowing One Address Per Order.