An operator can alter (expand or contract) a signaling structure by issuing the SETXCF START,ALTER command. This might be a response, for example, to changes in the signaling workload, to changes in the number of systems using a structure for signaling, or to performance information.

To enable such a structure change to occur without disrupting any connecting systems, CFLEVEL=1 or higher must be specified in the preference list for the structure.

To accommodate expansion of the structure, it is recommended that you define the INITSIZE (initial size) and SIZE (maximum size) keywords for signaling structures so as to allow room for future expansion of the structure,