Method, apparatus and system for mobility control

A method for a target secondary node, the method comprising:

• receiving, from a master node, an addition request message comprising a conditional indication, and
• transmitting, to the master node, an addition request acknowledge message with identification information of a target primary secondary cell in response to the addition request message,
• wherein the identification information of the target primary secondary cell in the addition request acknowledge message is generated, by the target secondary node, in response to the conditional indication of the addition request message.

A network node comprising at least one processor, wherein the at least one processor is configured to:

• transmit, via a transmitter to the master node, a change required message, wherein the change required message comprises a conditional indication for indicating the master node a secondary node change procedure indicated by the change required message is a condition based procedure.