The right to become a manager of a joint Hindu family depends upon the fundamental fact that the person on whom the right devolves is a coparcener of the joint family. Coparcenership is a necessary qualification for the managership of a joint Hindu family.
As a general rule, the father of the family, if alive, can be the manager or karta of HUF, or in his absence, the senior male member of the family, is entitled and presumed to be the manager of the joint family property with the consent of others.
The HUF would continue as such till it disrupts. The rule of survivorship applies to joint family properties. The senior most male member of the family for the time being is ordinarily regarded as the karta of the joint family. The senior member may, give up his right of management and a junior member may be appointed manager.
So far as income tax proceedings are concerned, all that is required is an intimation to the concerned Assessing Officer of the fact of the death of Karta and the appointment of eldest (senior) member as the manager of the HUF.
Further, you can apply for a change in PAN data by giving an affidavit by the senior member now being the karta of HUF stating the name, fathers name and address of all the coparceners on the date of change alongwith copy of any document applicable in case of an senior member as proof of identity and address.