Would anybody refer me to an attorney would could help me with a simple tax appeal in Pittsburgh?

Does anybody have any thoughts on that process, what I should do, and what my chances for success are?

I'm about to get into contract on a property assessed at $100k, but I'm only paying $50k for it (this is a fair ARV. No major repairs required).

So unless I can have it reassessed, I'll be paying double the tax that I ought to be.

One immediate question: I know that I'll need an appraisal for the appeal, but should I get that now while in contract, or wait until after I close?

Thanks!