There's a box to check on the form 610 where you can either keep your callsign, or upgrade to the next sequentially available one.
Jim
And since they a probably are out of the 1x3s you will get another 2x3 call. Keep your current call and when you get to Extra then go for a 1x2 or 2x1 thru the vanity route or your favorite call the you have in mind.
Rick wn2c