Negotiate with Bank on Owners behalf?

[Luke Petrozza]

Hello All!

I am looking for some advice on how to discuss a mortgage that an owner is going to leave in his name as i buy the property "subject to". 

The owner is looking for payment relief as the $1200 payment is @ a very high interest rate on only $73k principle. What would I need to be able to legally talk to the bank on the owners behlf to see if I can negotiate a lower monthly payment?

Is this a good idea to try to get some cash flow out if the deal as well?

Thanks!

Luke