This is a bit weird, but here's how. If you've already paid your fees, then you can NOT do this.
Go ahead and start with Deluxe and enter your personal information. After entering the name, SSN, etc of the first taxpayer on the return, click the "My Account" link at the top right, and select the "clear and start over" option. A few more clicks and you can chose the version you want to start with.