Due to financial difficulties, unable to pay the credit cards, but due to get some financial assistance which will enable me to pay them off at a reduced rate, but how do you negotiate to a fair agreed rate?

Call customer service and explain you cannot pay what you owe and need to close the account.
Suggest a low amount as the paid in full amount. Start with 30% of what you owe

I am planing to buy a new Steinway & Sons baby grand piano, model S, and it costs 49 000$. I know it’s very expensive for a piano, and I’d like to ask the Steinway retail store’s manager to give me a good discount. Usually a new piano can get a discount from 15% to 25%, and that can save me lot’s of money! But I need some advice on how to negotiate, thanks!

I have always found it helpful to start the negotiation by saying "is there anything you can do for me on the price" or something similar. Also, knowing the product, features, comparable competitors, etc. helps you to get a better idea of what a fair deal will be.

Also, sometimes I’ve been happier with deals where I just went back and forth a time or two. If you get too worked up with the negotiation, it can ruin what would otherwise be a decent deal. Enjoy the piano!