An enhanced agreement method and system to consent to a prorated value of a coupon of an E-ticket corresponding to a multi-segment transport involving at least two carriers for the transportation.The invention is based on a new system architecture, which comprises on each carrier side synchronous connections between various modules amongst which an E-ticket Server, a proration module arranged for calculating coupon prorated value, the system enabling to exchange coupon prorated values between both carriers from E-ticket issuance and before coupon usage.Further, based on E-ticket information and said exchange of coupon prorated values, the invention is arranged to launch an agreement process before or at a time of providing the transportation service.Another aspect of the invention is that information on coupon prorated value is embodied within industry standard messages that are already exchanged in current processes.