Most people are talking about reversing miles posted to another airline and then applying those to A3's program. As a heads up though, when I contacted A3 to request the opposite procedure (reversing miles posted to A3 in order to post another *A carrier) A3 said that once miles are posted into their account it is IMPOSSIBLE to reserve that.
Just an FYI in case you happen to be in the same situation. If someone has had a different experience, please let me know. I spoke directly with an A3 representative based in Greece.