Of that, I am unsure. I know you can modify the appearance of your Shepard, but I don't think you can change the pre-service history because that has to do with, not only the plot, but how many Paragon/Renegade points you start out with. I think that if you want to change your pre-service history, you have to make a new Shepard. Then again, we don't know all of the features of the file transfer system yet, and we won't until the game releases, so I can't be positive. I wish I had more to tell you.
Uh, how should I put this: NO. - MA4585159 08:53, January 22, 2012 (UTC)
Don't be so radical. You can change you pre-service history by using the Gibbed Save Editor. It allows you to change your ME1 import flags, which include values for "origin" and "notoriety". Changes take effect when you import the modified save file into the next ME2 new game+. There have been reports that they would even take effect if you modify your save file prior to leaving the Lazarus Facility, but I haven't got around to test it yet. Mitranim 09:03, January 22, 2012 (UTC)
^ Yes it does indeed work to modify it right when the game starts, I always do it that way to fix bugs like Conrad Verner and others so you don't have to play through a character with choices you didn't want. Just make sure it's done BEFORE you leave the Lazarus Research Station (preferably right after you wake up, but I don't think it matters) or it could damage your savegame.
But bear in mind that if you edit your savegame and it won't import correctly to ME3, we don't take any responsibility (but importing will probably work ok). Dogmatix314 16:58, January 22, 2012 (UTC)