Answer 1

Evolve the Ralts you traded from Yancy / Curtis.
You can also PokeTransfer or trade.

Source

Comments

Wow you traded him :D

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bye 2 minutes, I'm getting better! TBB will BA you becayse you're a Mod...

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I was looking for for a way for a specific Ralts to be obtained.

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How do you trade with yancy

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When you find her XTrancevier in Nimbasa City, she calls you in specific spots around the Unova Region. After returning the item to them at the Ferris Wheel, she goes to work. After that, she will be available randomly around the same spots, this is when you call her. After calling her 50+ times, she will call up to trade. There are a variety of Pokemon she can trade, so be patient.
http://pokemondb.net/pokebase/100997/how-do-you-get-yancy-curtis-to-call-you

Answer 2

Either catch a ralts or kirlia (if you can catch one) THEN evolve a FEMALE kirlia into a gallade or for another (lazy) way you can trade for it and automatically register. Other than that to secure the answer for anyone elses questions GET THE POKEMON AND IT WILL REGISTER.

Answer 3

• Fight a Trainer that owns it
• Fight it in the wild (not possible)
• Capture it from the wild (not possible)*
• Evolve a male Kirlia with a Dawn Stone*
• Migrate from Gen III*
• Transfer from Gen IV*
• Trade with someone who owns it*

*= registers the full Pokedex entry