So basically since 4.0 we are allowed to have more then one pet out in and out between the stable but I found out if you dismiss the pet and summon a new one you can use the exact same CD again.
What this can be used for?
Playing arenas you can do Roar of sac after the 10 seconds dismiss pet get new one and do it again later on in the game.
In pve you can do call of the wild dismiss pet and summon a new one for another CotW.