Convince my parents to let me get a new pet?

Okay so I want to get a west highland white terrier and I alredy have a doxion mix…my dog gets lonly and doesn’t eat when we aren’t around and I’m not always there to play …how can I convince my parents to get a new dog?

I was thinking about cleaning the entire house on a sat morn when my parents aren’t around and when they get home and rest sit them down and have a serious talk… Maybe I can name the pros and cons and they can say the. Cons they can think of and try change there mnds ..thanx for ur help