In my view, section 81 resolution requires to be passed by a public limited company before the right to claim equity share arises. Therefore, simultaneous with the class meeting under sec. 106 for consent from the preference shares, hold the general meeting and pass sec. 81 resolution though the actual process may come after some time gap. You can also take it that you should do the conversion within 12 months of passing sec. 81 resolution as required by the Unlisted Public Companies Preferential Allotment Rules, 2003. Therefore, ensure that you are within this time frame.
G-156/F-2, Dilshad Colony,