i'm guessing their your starter and partner. you have to beat the game plus the post-game, ending with the darkrai battle at dark crater. stock up for it though. darkrai can KILL you unless you throw things at him and have good moves if you can't get to the next event, keep doing missions until something happens. after you beat darkrai, keep doing more missions until manaphy comes back from the sea and lets you go to marine resort. then you can evolve, but you don't have to go to marine resort. who said you needed a lunar ribbon to evolve? they deserve a slap.
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You need to recruit palkia at spacial rift to evolve your starter and partner.
Not if you have the Lunar Ribbon... Which petlover has...
Also to go to Dark Crater just talk to Cresselia who is outside of the partner's home...
Also for that method you need Dialga and Palkia to be on your team...
In the future, post only one thread. :| If people aren't replying in one, chances are making another won't do anything more than clog the forum and annoy people.
if i knew what part of the post-game you are at, i could help you. where are you at? did you beat Aegis Cave? tell me what major dungeon you have to go to now. then i can actually help you.