to sell land jointly owned my members

i am a joint holder of half acre land located in good urban residential area.

as it is some of the members whose names are on 7/12 record of land,are willing to give up their share without anything in exchange.

it is upto me to start and finish the process of selling land.

so which documents do i need make and get signed from those willing to give up their ownership claim to land?

kindly guide, thanking you in advance.