The property is on whose name???
The gift cannot be made for consideration (money) if your are asking money than it would constitute sell and then stamp duty for sale has to be paid.
Also it is has to be seen on whose name the house is as if it was in joint name of both parents than on fathers share all children and mother has equal right and in that case all of you can make a relinquish deed in favour of sister.
Also to save tax the amount shall be considered as capital gain and youncan incest it other residential property to get exemption under section 54 income tax act.
Kindly clarify the title of property on whose name.