30 Amp

hi everyone, I just bought a washer and dryer for my RV. My box only have a 30 amp and 20 amp recepticles..to add another 30 amp, would I need a new box? I know I could disconnect and reconnect my rv everytime I decide to use the dryer but I don't want to do that everytime. Is there a way I can just add a 30 amp?