Buying a new blackberry at&t?

[DaT_GuRl]

I'm thinking about ordering a blackberry bold over the internet. I recently have the Lg Vu. If i order the phone over the internet, i have to pick a blackberry plan and all that crap. what i'm wanting to know is if i order and change the plan over the internet, will i still be able to use my Lg vu until my blackberry gets here? Thanks in advanced...