AlaCritical Hit
Brother my brother
From what I've heard, you can just run away to re-encounter the Eon Ticket Lati@s without having to beat the Elite Four. This is more efficient than soft resetting as it is quicker without having to go through the title screen.
I know that you can re-encounter the Eon Ticket Lati immediately after running from it or defeating it. I'm not sure if shininess also resets if you use this method.