Original sentence: A three times a week service  to Islamabad with Pakistan International Airlines began in July, utilising Airbus A310-300 aircraft.but it is heavily rumoured that PIA will be changing this servise to utilize the Boeing 777 aircraft by the end of October 2009
Edited sentence: A twice   weekly service  to Islamabad with Pakistan International Airlines began in July, utilising Airbus A310-300 aircraft, but this service increased to a three times a week service within the first 6 months of operation.It is now heavily rumoured that PIA will be changing this servise to utilize the Boeing 777 aircraft by the end of October 2009