liability waiver

Is this sentence formal and correct? Would I have to change it if I I wanted to use it in a document? Is it fancy enough?
A liability waiver, if signed will waive all responsibilities you may have had had you not signed it.

How wold you have asked the following 2 questions yourself? Would you have said: 1 Would I have to change it if I I wanted to use it in a document? 2 Is it fancy enough?

Thanks