If you use an inertial (hammer-like) bullet puller, whack it a couple of times to lengthen the seating depth, then reseat to the desired depth. If a bullet comes out, pour the powder back in and seat the bullet. If you use a collet bullet puller, the bullet will be damaged by the puller, in which case you will have to pull and discard the bullet, then seat a new bullet to the desired depth. Either way, you do not need to resize if you are going to shoot these cartridges single-loaded. In fact, they will likely be very consistent with regard to neck tension. I have done this to sized cases before priming or loading, to make neck tension more consistent. It's just a pain. What I do now is size the neck with a Lee collet/mandrel die, then run an expander mandrel down the necks. That results in a bit more neck tension, certainly not excessive, and very good consistency. If you're going to change the primer, go ahead and shoot these, then change the primer component of the load, and compare the two. Some push out live primers, but I don't recommend it, and I've never done it, because I don't want any accidents. Sometimes your first accident causes irreparable damage.