(8)is inadvertently and undersignedly spoiled and in lieu whereof another instrument made between the same parties and for the same purpose is executed and duly stamped :Provided that, in the case of an executed instrument, no legal proceeding has been commenced in which the instrument could or would have been given or offered in evidence and that the instrument is given up to be cancelled.Explanation. - The certificate of the Collector under section 32 that the full duty with which an instrument is chargeable has been paid is an impressed stamp within the meaning of this section.
