On heart gold how to make misty return her gym?

You can't make Misty return to her gym in HeartGold. This is because she leaves to go on a quest to find her Psyduck and won't be back at her gym until after the main story.

Here's what happens:

* After you defeat her in the gym: Misty leaves to find Psyduck, who ran away during your battle.

* She will only return to the gym once the main story is complete: This happens after you defeat the Elite Four and the Kanto champion, Red.

* Upon her return, she will be available to battle as a trainer, but not for gym badges.

So, while you can't force Misty back to her gym before the end of the game, you can re-challenge her once the main story is finished.