As per the query ,does the share in flat standing in the name of yourself and your friend or does it stands individually in your name as per the sale agreement.
If, the flat stands in the name of yourself and if you like to transfer the flat in the name of your friend then it will be transfer in the eyes of law and shall attract stamp duty and re registration of the document as per the market rates which has to be checked in the respective registrar or sub registrar office in whose jurisdiction the flat is situated.