How many times does Yancy have to call you to trade Spiritomb in black2?

In Pokémon Black 2, Yancy will call you a total of 10 times before she offers to trade you a Spiritomb. You must have a specific Pokémon in your party for her to initiate the trade, and the calls will occur as part of the game's post-game content. After the 10th call, the trade can be completed.