How to Unlock[]
In Festival Square, there are four sets of balloons with one that's not colored. Two are in the little circle area south of the Call-In Point (one needs red, the other needs yellow). The third is near the clock tower and needs blue, and the last is some ways northeast of the clock tower and needs yellow. The Red Color Swapper is in the building northeast of the hospital, and the blue and yellow swappers are further east of that, in a building with a revolving door.