Even as you reach to open the door, you're still fiddling with the app. You manage to generate another sentence as the door swings inward.
"This young woman is thankful to her classmate for the chance to calm down."
You smirk. Time to get rid of your slobby roommate and replace him with someone a little hotter. "Come on in," you say, even as you make the change from "classmate" to "roommate".
"Sorry to impose," Kelsey apologized. "I just, um, needed a moment." She sits down on the edge of the other bed in the room, looking a little flustered. You frown, wondering why nothing has happened. When you look at the phone, you realize that it has highlighted two words in yellow ("woman" and "her") and one word in orange (the one you changed, "roommate"). At the bottom of the screen is a small box of text: "Primary change unavailable in free mode. Use secondary change, or pay $1000 for full version?" Well, you certainly don't have a thousand dollars to pay for this, so you click the "secondary change" option and confirm, confident you're about to turn your room coed.
In a flash the room suddenly changes, but not how you expect. As you look around, you are struck by a sense of pink. There actually wasn't an excessive amount of it, but the sudden absence of dark blues and greens that formerly made up your bedding and pillows makes the new pink décor pop more. But wait, why did _your_ stuff change? It was supposed to be your roommate that got replaced. Then you glance down and realize something else was different - your body.
Between you and the screen of the phone is the swooping neck of a black tank top, even though you had been wearing a T-shirt only moments ago. More noticeable than the shirt is what fills it - two mounds of flesh that swell into the rounded cups of a bra under the fabric of the tank top. You don't need to see the narrow waist, wide hips, and skinny jeans hugging slender legs to confirm it - you have become a girl.
"You, uh, okay Gina?" Kelsey asks. You blink. Gina? Is that your name now?
"Yeah, um, one sec," you say. Your voice, not exactly super deep before but certainly manly, now comes out several octaves higher and lighter in tone. Long strands of brown hair have fallen into your vision and you instinctively brush them back before remembering your hair wasn't supposed to be long. You have to figure out what happened.
You quickly open up the app's main menu, and to your relief you find a listing of the last changes. Under the heading for the most recent change, you finally find out what it meant by primary and secondary change. The program had resisted the primary change - changing Kelsey to be your roommate - because you were in a single-gender-only room and making it coed sent out successively greater ripples of change through reality. The secondary change was much simpler and easier to accomplish - it simply made _you_ female. Now, apparently, you were roommates with Kelsey.