If a muslim converts from Sunni to Shiite, are all of his past sins erased?

OR if a Shiite converts to Sunni, is it the same as when a non muslim reverts to Islam it is said that he is born again and all of his past sins and actions are taken away. does the same apply if a Sunni convert to a Shiite OR a Shiite becomes Sunni ? ( depending on your viewpoint as to what the true Islam is)