This field allows you to indicate how you want to handle the address towers for the node registration. You can enter one of the following keywords. These can be abbreviated, as long as the abbreviation is unique. Modify - Modify the current address towers. If the node is being registered, this allows you to enter new address towers. If the node is being modified, the old towers are presented as defaults, and you can change, add, or delete address tower information. Keep - Keep the current address towers. If the node is being registered, it has no current towers. Use this to indicate that no towers are to be registered for the node. If the node is being modified, the current address towers remain unchanged. Replace - Replace the current address towers. If the node is being registered, this allows you to enter new address towers (this is equivalent to modify). If the node is being modified, the current towers are deleted, and you are asked for a new set of towers to be registered for the node. Delete - Delete the current address towers. If the node is being registered, it has no current towers. This indicates that no towers are to be registered for the node (this is equivalent to keep). If the node is being modified, the current towers are deleted. You are not asked for a new set of towers. If you answer replace or modify, another form is brought up to allow you to enter the address tower information. If you answer keep or delete, you are asked if the node should be registered or modified. You can proceed or cancel the operation at this time.