This feature is currently incomplete, in that the option to reconfigure is only available when integration has a functioning connection with an existing zwavejs2mqtt server.
To add to the injury, even when it does, changing it to point to same service (thru another IP) fails with the following error:
“The connected USB device is not the same as previously configured for this config entry. Please instead create a new config entry for the new device.”
Without this feature, in order to migrate zwavejs2mqtt to another server (e.g. a raspberry Pi), someone is forced to either recreate the integration record and re-edit all entity-ids, or maintain an ssh tunnel from the old IP to the new IP.
The IP address for each instance of the integration is saved in home assistant’s configuration directory in config/.storage/core.config_entries. Look in this configuration file for the domain keys with value equal to zwave_js. Then look for the url key in the same entry.
To modify it, just shut down home assistant, modify the url key’s value to the new IP address of your zwave-js host, then restart home assistant.
Proceed cautiously when editing configuration files in the config/.storage directory (or anwywhere else, for that matter). Make a backup before you start editing.