Is it possible to buy eyeglasses and then have the frames changed to near-sighted ones?

Frames no effect.: The type of frames one get has nothing to do whether one is near or far sighted. Only the actual lenses do.

Change the glass: Frames are just to hold the corrective lenses in place, so changing the frame will have no effect on the power. If you find an eyeglass frame you like, an optical shop - with the proper prescription - can replace the old lenses with your prescription to fit the frames you like.