At the 14:37 mark of this video you can see Bill Howard fix the centering on a blade. He has what he calls a kick press that puts pressure on the tang, which is softened for this task, and that kinks the blade so that it's centered in the frame.
[video=youtube;xA-OpahW7EA]https://www.youtube.com/watch?v=xA-OpahW7EA[/video]
I don't have that press, but a while ago I had a knife with a blade that was rubbing the liner and I decided to see if I could simulate that process myself. What I did is put the blade into a padded vise so that the whole blade except for the tang is in the jaws of the vise. Then I push or pull the knife in the direction that would bend the blade to where I want it to be. It took a bit of practice to get a feel for how much pressure to apply, but I've gotten to be OK at it to where I usually don't have to go back and bend it the other way because I went to far anymore. This will loosen up the joint, so then I close the blade and put that end of the knife in the vise with a gapper inserted next to the blade tang and give it a squeeze to tighten it back up a bit. Then I usually have to hit the bolsters with some sandpaper because the pin is now showing.
It's not a really tough process, but it is a bit more involved than filing down the kick or something like that. I'm just a stickler for blade rub, and there was a knife I really liked other than the blade rub so I took a chance and it worked out. Now I can center the blades on most knives without too much stress. Some knives seem to have a tang that's just wonky and when I squeeze the bolster back together the blade moves back to being off-center again. I don't mind an off-center blade as long as it's not rubbing. I can usually at least get them to not rub. I'm sure there's a better way of doing all of this, but this is the method I came up with and it's worked for me.