Dave
When you take your exam at a VE session, there is a space on the form 605 to indicate whether you want another "FCC assigned" call sign. However if you are upgrading from Tech to General, the FCC will assign you another 2 x 3 call. However once your General license is granted (i.e. appears on the FCC database), you are eligible to select 1 x 3 vanity call. When you get to the top with the Extra license, you can get a "FCC assigned" 2 x 2 call beginning with the letter A. If you want to be creative, you can select a 2 x 2, 1 x 2, or 2 x 1 vanity call sign. When you pass the required exam elements for your General upgrade, you will receive a CSCE (Certificate of Successful Completion of Examination) from the VE team. This will allow you to use your new General upgrade privileges by adding /AG after your present call sign on CW or "temporary General" after your present call sign on phone until your upgrade appears on the FCC database. The "paper" license should appear a few days later. Remember, you keep your present call sign until you decide to change it.
Bill KA9ZBN