There is no any provision for amendment in affidavit filed as exa.in chief but additional affidavit may be filed with permission of the court before cross examination. There is no provision for filing additional affidavit as well but under 151 CPC the Court has inherent power to take on record such additional affidavit. My suggestion is that only typographical errors may be corrected by additional affidavit. The fact must not be described contrary to previous affidavit.