Forms needed for society share transfer to nominee

My father owned a flat in a society and had nominated my mother as the sole nominee. My Mother, after his demise in recent past, now, wants the share certificates to be transferred in her name. She does have independent source of income and is capable of paying society dues in future. What are the forms to be filled and documents needed for this transfer? a) the secretary has given us a form that is actually meant when there is no designated nominee. b) A local stationary shop gave us a bunch of forms meant to be used dusing sale of the flat wherin the transferor's signatures are needed. Both do not appear to be appropriate in my mother's case. Please help.