Letter of Administration

Hi, my grandfather received company shares as part of his compensation during his service tenure. He expired in 1981 in Bihar (hometown) without leaving behind any will. After contacting the company to transfer shares in my dad�s name, they are asking to produce either succession certificate or letter of administration. My dad also expired last month. My question is, Is it possible to obtain letter of administration in any other state (currently residing in Mumbai)? What is the legal process?