Yes, talk to a Pet Trainer (1 outside Ascalon City, 1 outside the Sunspear Great Hall & 1 outside Shing Jea Monestry) and you can get rid of both your own as well as your hero's pet's.
You could read the update notes about it if you don't believe. Or you could just go and try it for yourself. Do you REALLY need confirmation for something like this?
