No proceedings instituted by the City Council under said citation, nor any proceedings subsequent and pertaining thereto, shall be void on account of any failure to give notice to any person or persons interested therein or shall for that reason be dismissed, but such proceedings shall be suspended till such person or persons are duly notified; whereupon the same proceedings shall be had in the same manner and with the same effect as if such person had been duly notified by the original citation. If the person so notified shall appear, he or she may be heard upon all matters therein pending in which he or she is interested.