What does it mean to change airlines?

Flight dynamics change. Ticket change usually refers to changing the flight departure date of the ticket under the condition that the carrier airline remains unchanged, which is equivalent to rescheduling. Ticket change includes two types: change and signing. Change, also known as rescheduling, refers to the change of guest itinerary and carrier airline. Signing refers to signing between different airlines. It refers to changing airlines after purchasing air tickets. For example, if a passenger wants to change to Air China, it is a transfer. Signing is only applicable to full-price ticket guests, and discount tickets cannot be signed.