Before deleting a node, you should first
Remove it from any enabled partition by unsetting its partition attribute (automatically removing the node from the partition's nodes attribute list), or by removing it from the partition's nodes attribute list. See "Partition Attributes" for details.
Wait for any jobs running on it to terminate, or stop them using the mpkill command, which is described in the Sun HPC Cluster Runtime Environment 1.0 User's Guide.