Dismissing a Pet----------------If you currently have a pet already, you CANNOT charm a new one. If you wish to change your pet, you need to hand it over to a tamer. The main tamer (Jarrel the Tamer) in Post-Searing Tyria is just outside the gates of Ascalon City. There is a Tamer next to Master Ranger Nente (who gives you Charm Animal for the Ranger subquest) in Pre-Searing Ascalon.
Here you go you ranger people. Pet infoA little tidbit of what is written there...There is a lot more for you to read though. I hope it helps.