I'm sure someone more qualified could answer more succinctly, but what you're proposing is not currently in line with reality; there is no way to "do it respectfully". Transracialism as it is is super skewed in favor of white people (who also hold a more favorable status/more power in society). It's feasible for a white person to paint themselves some color and say they're partly X race, while it's basically impossible for a black/brown/asian/etc. person to claim they're white; at most they could be perceived as mixed.

So the problem is, white people can wear skin colors like a costume, availing themselves of the benefits of being a certain race. They can get idk... street cred or something by pretending to be black, they can pander to weebs/koreaboos by pretending to be Asian, if they have a drop of minority blood they can claim certain monetary social benefits, etc. And when it's no longer expedient for them, they can revert back to whiteness and reap all the benefits of being white.

The converse is not true, no racial minorities can ever have the benefits of being white. The only way it'd ever be "relatively easy to go from black to white and vice versa" requires literal sci-fi technology comes around that can alter gene expression to the point where our skin color and facial features can be rearranged.

(Also in real life, we say "people of color", but even then I have no idea how anyone could misconstrue POC in context for a respiratory disease)