WotLK Dungeon boss doesn't respawn?

[Jenura]

I've never played WoW before playing on Warmane, so please excuse my inexperience.
I'm attempting to farm Baron Rivendare for his mount, but despite all the trash mobs respawning in the dungeon instance, all bosses remain absent.
How does this reset work?

[Aoto]

Just to verify, since some mobs do respawn there...are you killing Baron, leaving the instance completely, then resetting the Instance (using the option to reset it), then re-entering the instance, and Baron is still not showing up?

[arcsperia]

It should respawn if you go out, right click on your portrait and reset instances

[Jenura]

I didn't know it worked like that, thanks!