Hello, I'm an expert in Pokémon games and their mechanics. In the Pokémon series, Meloetta is a unique Pokémon with the ability to change its form between Aria and Pirouette. The move Relic Song is a special move that Meloetta can learn, but it's not typically taught through regular gameplay methods.

To teach Meloetta Relic Song, you would need to participate in an event that allows you to do so. These events are often held by the game developers to celebrate special occasions or anniversaries. Once you have the opportunity to teach Meloetta Relic Song through an event, you would typically receive a special item or code that enables you to teach the move to your Meloetta.

Here's the translation in Chinese:

你好，我是宝可梦游戏及其机制的专家。在宝可梦系列中，梅洛艾塔（Meloetta）是一个独特的宝可梦，它能够改变其形态，分为咏叹调（Aria）和旋律形态（Pirouette）。古老之歌（Relic Song）是一个梅洛艾塔可以学习的特殊招式，但通常不是通过常规游戏玩法方法教授的。

要教会梅洛艾塔古老之歌，你需要参加一个允许你这样做的活动。这些活动通常由游戏开发商举办，以庆祝特殊场合或周年纪念。一旦你有机会通过活动教会梅洛艾塔古老之歌，你通常会收到一个特殊的物品或代码，使你能够将这个招式教给你的梅洛艾塔。

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In X and Y, an Ace Trainer in Snowbelle City will teach Relic Song to Meloetta. In Pok��mon Omega Ruby and Alpha Sapphire, the Move Tutor is located in Mauville City. In Alola, the Move Tutor is located in the Hano Grand Resort.read more >>