Can I or how can I replace the A/C knobs in a 2002 Nissan Altima to a newer altimas knobs?

I would only let a dealer perform this function. the knobs may not be the same and once you discover this yourself, it may be too late. let the dealer advise you.

Are they simply turning knobs that don’t necessarily ‘click’ but feel like they have notches in them? Usually, knobs are glued onto metal, mostly-cylindrical rods; they are cut vertically along a certain chord. when a matching hole is connected to this rod, it turns the rod with multiplied force depending on the size of the knob.

Little things like this can change very easily. Consult with your dealer to make sure if that transfer would work.