So I just recently interested on Bitcoin vanity address, and I generated some cool looking address. And then this idea came out, how can I give or sell people these vanity addresses that I've found?
Is it possible to generate an address and then give the ownership to someone?
Is there any way that I can remove the first private key and then my friend make a new one for himself?
The problem is you can't really sell an account you've already generated as "safe", as you have seen the private key... any account where the number of people who have access to the private key > 1 can not be guaranteed to be secure. Much the same way any "secret" that is known by more than 1 person is not a secret. Unless the person trusts you implicitly, they should not consider buying one of these addresses from you.
However, if you were to start doing "Split Key" account generation as used by other Vanity Address generator services, then they are "safe" (assuming the recipient follows best practice and runs the private key generation on their own hardware and doesn't do something dumb like use a website to calculate the keys) and should be able to be used without issue. (Ignoring other Vanity Address issues)