1. A system for delivering content to a client device while the client device is in a session with a server, the system comprising: a first presentation system configured to deliver content, formatted for a first presentation mode, to the client device via a wireless access network; a second presentation system configured to deliver content, formatted for a second presentation mode, to the client device via the wireless access network; and a session manager configured to, during the session: transmit content from the server to the first presentation system for presentation to the client device in the first presentation mode; maintain a state record associated with the client device, the state record defining a current state of the session with the server; receive a mode-switching signal; and responsive to the mode-switching signal, transmit content associated with the current state of the session to the second presentation system for presentation to the client device in the second presentation mode; thereby continuing the session in the current state.