Indian Oil Corporation [IOC] — name change

Address:

47/4, Jaynarayan Banerjee Lane, Baranagar, Kolkata, West Bengal, 700036

Sir,
I want to name change of our gas connection because this connection has been on behalf of my mother. But my mother health haven't well. So, he can't operate his bank account. Therefore his bank account some problematic. So, i want to change this on behalf of my name. So, please reply me what is the procedure to change it? Our present consumer number is [protected], under baranagar gas service.