If you're talking about the outer races in the steering neck of the frame, you can get them out easily with a pair of holes drilled 180 degrees apart and a suitably sized drift or prick punch.
Seal the drilled holes from the outside with a dab of silicone if you're concerned about the new bearings becoming contaminated.
It's not generally considered good practice to mix old and new bearing surfaces. Tolerances and machined surfaces on modern production bearings are quite remarkable. One of the wonders of modern mfg'g.