Forego family assets right

Hi Guys, need some urgent help...

My wife's family is having dispute in the family and hence my wife needs to opt out from that dispute. She wants to forego all her rights in the family assets and walk away. For this i understand we have to make an affidavite and give it to all the family members... My query is what should be the process so that its fullproof and everyone in the family would accept the same.

Hope to hear from you guys.. ASAP..

Thanks

Nikhil