How do i talk my stepdad into getting a bet hound when i already have a beagle?

i have a beagle and shes 24 months and i show dogs i like hounds and i know my daddys frend hoo is giving bets away my mom says yes but my stepdad ses no and how to i make him say yes i already sed after i get straight as at school i could but i wont i need more reasons y i desrve one