Use a spoke tool to "unbuckle" or straighten rim.
On a tire that size should take just a couple minutes.

Shoulsn't take long at all. I'll dumb it right down for you:
You'll notice that the spokes from the centre hub to the rim meet in a straight line on the rim but go to either side of the hub. What you need to do is determine what spokes need to be loosened or tightened to move the rim & remove the buckle; if the rim buckles to the left, find the centre of the buckle & loosen the spokes that go to the left side of the hub & tighten the spokes that go to the right side.
Seriously, it's not that difficult. The hardest part is getting the spoke caps to actually turn. Removing the tyre will help in two ways; 1. it removes a bit of pressure from the rim & 2. it exposes the end of the caps which have a flathead slot in them.
Have a go at it & see how you go. Once you remove the tyre, mount the wheel back on the scooter & your brakes will act as a guide...