Thanks @eris As I see it there is no way to change network from the panel.
So my conclusion is to do it manually.
Can you clarify those are the right steps?
- v-add-sys-ip (new)
- Change all users web and dns to the new ip
- v-delete-sys-ip (old)
- Change the gateway on the interfaces file
- v-update-sys-ip
- v-rebuild-mail-domains
- Reboot the server and pray …