how to increase bank OD without extending registered mortgage?

i am having OD account with a nationalised bank. the account is standard and i am considered as a VIP customer by the bank, but my OD is secured by a registered mortgage of my relative’s property and i do not have any landed property of my own. i do not want to approach my relative again for extension of the RM. is there any way to increase bank OD without extending RM appropriately?