http://www.anonimfiles.com/how-to-change-your-psn-id/
In this video I show how easy it is to change PSN ID on the PS Vita. In this video I'm changing from a US PSN ID to a JAP PSN ID, but this is the same method done for switching PSN IDs regardless of region. Memory card will not be formatted if you choose not to,
how to change psn id name on ps3 without making a japanese account and without having to lose all game data on user
