Can anyone suggest the most effective way to get B of A to waive their right to pursue deficiency?

I received a short sale approval from B of A with the clause saying they can pursue the deficiency:

"BAC Home Loans Servicing, LP and/or its investors may pursue a deficiency judgment for the difference in the payment recieved and the total balance due, unless agreed otherwise or prohibited by law, if the short sale closes on the loan referenced above."

And I know that they, or a collections company, can do this. You are only protected from this on a foreclosure and with a non-recourse loan. There is a myth that you are also protected in a short sale but you are not. (I have a non-recourse loan, first only, and always owner-occupied property.)

I am trying to get B of A to drop their clause and to waive their right to pursue a deficiency, but it is slow going trying to find someone empowered to do this.

Has anyone here done this successfully? Please provide me your suggestions for how to do so.

Thank you.