unicycle seat

I’m just curious but what do u think the is easiest way to make a unicycle seat. And is there a way to make two parent objects non parent.

     Thanks

Depending on how high-quality you want it to look, here is one way that you could do it. Go into edit mode and delete the cube that you get when Blender starts up. Control + Left-Click to add a couple of points that roughly follow the general shape of the seat. Go to side view and extrude these points down. When you turn on subsurface smothing, and set it to around three or four, it should look sort of like a unicycle seat. For a bit more high-quality of an apporach, you could do something like this: make a plane and subdivide it a lot. Then, turn on proportinal editing (the O key) and drag some of the virtices down. The proportinal editing should drag some more down with it, giving you a pretty smooth curve. With some work, you could get a pretty nice seat. Those are just a few of the ways that you could do it.
As to parents, I am not quite sure what you meant. I think that to clear a parent, you just press Alt. + P.