Well, to to settings ... duuuh.
Yeah, alright, but what if I have to run headless, i.e. not have a monitor or TV attached.
So as long as you can ssh into it (i.e. you know the current IP address) you can do
connmanctl config "$(connmanctl services | awk '/^\*/ {print $3}')" --ipv4 manual 10.0.0.22 255.0.0.0 10.0.0.1
The "inner" connmanctl finds the service name for the active IP connection, the "outer" one changes it to the new IP