Abstract: A method for changing the state of a pre-booked ticket from a first booked-state to a second check-in state, wherein the method includes a mobile device communicating through an IM communication system with a check-in desk service. The mobile device also comprises an identification instrument for a user, said check-in desk service having access to the pre-booked ticket. The method comprises the steps of connecting the mobile device to an appropriate network in order to communicate with the check-in desk, sending the identification instrument through the IM communication system to the check-in desk in order to access to the pre-booked ticket, requesting to change the pre-booked ticket state from booked to check-in and receiving an electronic boarding pass on the mobile device to access to a boarding gate.