You would need a .473" (standard 30-06, 308, 22-250 etc.) bolt head (and either tranfer your ejector & extractor parts over, buy new ones, or buy a complete bolt head assy.).

Other than that, you would just need the tools required to take apart your bolt (punches, hex wrench or screwdriver, maybe a padded bench vise, etc.) Nothing complicated about it.

If it were mine and I had any idea that I might want to go back to a cartridge with a magnum sized head (who knows when you might need a 450 Marlin or 264 Win?) I would consider buying a complete bolt assembly (more $ but instant changeover).