How do you get an old pass in Pokemon sapphire?

You can't get an Old Pass in Pokémon Sapphire. The Old Pass is a key item in Pokémon Ruby and Emerald, but it's not used in Pokémon Sapphire.

Here's why:

* Different Storylines: Each game in the Ruby/Sapphire/Emerald generation has a unique storyline. The Old Pass plays a crucial role in the Ruby and Emerald stories, allowing players to access the Seafloor Cavern and confront the legendary Groudon or Kyogre. Sapphire's storyline focuses on different locations and events.

* No Seafloor Cavern: Pokémon Sapphire doesn't feature the Seafloor Cavern, the area where the Old Pass is used.

If you're looking to explore the Seafloor Cavern or catch Groudon/Kyogre, you'll need to play Pokémon Ruby or Emerald.