What can you do with the blue flute in pkmn white?

Question

So I got one near undella town and I thought what can I do with it ;$

Answer 1

You can sell it to a man in the mansion in Undella Town.

Comments

Same with the black flute?

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Yep. This works with all flutes except the Poke and Azure Flutes.(though you can't get the last two on this game)