Purchased company debentures in 1986.While purchasing the debentures,my brother name was indicated as second holder with out his signature on the application.Later,they were converted as shares and getting dividend in my name when ever it is declared.Now,the shares are in physical form and to be dematerialized. Please indicate whether they require joint or single demat account.It should be kept in mind that my brother name is reflected and his signature is not given on the application.