leading case law of supreme court on waiver

Evidence Act S 115-waiver of legally enforceable rights- has to be clear,unequivocal,conscious and with full knowledge of consequences.
Shashikala devi v central bank of india
Citation;AIR 2015 Supreme court 2434
Read full judgment here;
https://drive.google.com/file/d/0B5vWGtQ14k1BWU82Mm5URUpWQ00/view?usp=sharing