There is no reboot at this command.
ClusterXL_admin up makes the node again Active at the cluster state or makes the member Standby from Down?
Should be standby. But 2b sure I would consider having a look at the ClusterXL config.
If i am not wrong, with this setting, my answer should be correct. If "Switch to higher priority Cluster Member" is activated AND the affected device is the device with higher prio (on top of the Gateway Cluster members list in the Clusters Members Settings of the Gateway Cluster Properties), it will most likely become active member.
and now to something completely different - CCVS, CCAS, CCTE, CCCS, CCSM elite