Maybe the answer to this question is a simple and unequivocal "No", followed by "How can you possibly think that this is possible?". And if I think about it rationally this seems to be the only answer. But programming and math have taught me that a lot of things one intuitively judges as impossible or pointless may have a surprising answer. So here comes one of those questions.
Is it possible to convert a gpg RSA key to an ECC key? Or, to generalize, is it possible to switch between different cryptography algorithms for one and the same key such that one retains the key's functionality; signing and encrypting etc. If so how does this work and if not, why not?