+1 For the above recommendations, a heat gun or even a hair dryer (Just don't tell the wife!) will do the job if needed. The bearings can have a tight tollerance fit or even have a small amount of loctite bearing retainer holding them in place so a little heat will allow the metal to expand slightly and release the bearing and if there is loctite present it will soften that up and also release the bearing allowing it to drop free.
I usually get a couple of towels and use one on the table and one to hold the blade grip, then gently warm the grip with the heat gun/hair dryer for a few seconds and the bearing should drop out with a gentle tap.
To refit new bearings it is just a repeat procedure, first make sure everything is clean by just giving everything a wipe with a towel and then with the heat gun warm the grip up again for a few seconds and then pop in the new bearing and allow everything to cool. When cool the metal of the grip will contract and hold the bearing in place.
Hope this helps, if you have any further questions just give us a shout.
Cheers,
Ross