In Crimea, it has been reported, they give Russian passports to the people wanting them. This implies that they are getting a Russian citizenship as well and probably cancellation of their citizenship of Ukraine, because as as far I remember, Ukrainian laws don't permit having another citizenship. This is probably a pretty routine procedure there now, however a notable case occurred some time ago, as in one of the Crimean
villages a man, Yuri, came for his new Russian passport and failed to present his Ukrainian one - as reported by the Sudakonline local Crimean website. When asked where his Ukrainian passport was, the man said he refused to accept Ukrainian citizenship and for twenty three years held his old Soviet passport, and now he came to get a new Russian passport. There is just one photo here.