Power of Court to convert summons case in to warrant case is provided under:

As per CrPC, S. 259. Power of Court to convert summons- cases into warrant- cases . When in the course of the trial of a summons- case relating to an offence punishable with imprisonment for a term exceeding six months it appears to the Magistrate that in the interests of justice, the offence should be tried in accordance with the procedure for the trial of warrant- cases, such Magistrate may proceed to re- hear the case in the manner provided by this Code for the trial of warrant- cases and may recall an witness who may have been examined.