How to participate in buy back, if POA / DDPI is not updated in demat a/c ?

How to participate in buy back, if POA / DDPI is not updated in demat a/c ?

Client can submit Delivery Instruction Slip (DIS) duly filled and send the same on below address to DP for Buy Back. NSDL DP Department IIFL Securities Limited, 701,�Ackruti Centre Point, Central Road, Marol MIDC,�Andheri East, Mumbai - 400093�