**Mandatory.** Must be implemented by all level I devices.

This event can be used to change the nickname for a node. The node just uses the new nickname and don't start nickname discovery or similar.

Standard form. (Mandatory).

 | Data byte | Description | 
 | :---------: | ----------- | 
 | 0  | Old nickname for node. | 
 | 1  | The new nickname for the node. | 

 Extended form that can handle 16-bit nickname (not mandatory for devices with 8-bit nickname)

  | Data byte | Description | 
 | :---------: | ----------- | 
 | 0  | MSB of old nickname for node. | 
 | 1  | LSB of old nickname for the node. |
 | 2  | MSB of new nickname for node. | 
 | 3  | LSB of new nickname for the node. |

Use data size to determine between 8-bit and 16-bit node-id format. A 16-bit node should handle a 8-bit nickname as a 16-bit node id with MSB = 0. It should handle also the 8-bit node-id version of the event.
