Embodiments of the disclosure generally relate to primary cell change. A network device detects whether layer 2 context being kept and/or one or more serving secondary cells remain for a primary cell change for a terminal device. Then, the network device configures a message indicating the primary cell change based on the detecting and transmits the message to the terminal device. The time period of primary cell change can be reduced efficiently and the data transmission during the primary cell change can be optimized.