Arup ji, it is perfectly legal for an advocate to appear on behalf of other advocate to seek an adjournment or conduct that days proceeding with a written authorisation from the advocate who is duly appointed by the party. And there is nothing uncommon about it. There is provision in the civil manual about it in para 652, I am pasting the relevant portion of it---
652. (1) No Advocate shall act for any person in any Court unless he has been
appointed for the purpose by such person by a Vakalatnama in the form annexed hereto
and signed by such person or by his recognised agent or by some other person duly
authorised by or under a Power of Attorney to make such appointment.
(2) No Advocate who has been engaged for the purpose of pleading only shall
plead on behalf of any party unless he has filed in Court a memorandum of appearance
signed by himself and stating (a) the names of he parties to the suit, (b) the name of the
party for whom he appears and (c) the name of the person by whom he is authorised to
appear :
Provided that nothing in subrule
(2) shall apply to any Advocate engaged to
plead on behalf of any party by another Advocate or Attorney who has been duly
appointed to act in Court on behalf of such party :