Hello Balubeto,
Ethernet will usually be handled automatically.
You could use the method in the tutorial below to remove a wireless network profile. You will have to manually connect to the wireless network again afterwards though.
Wireless Network - Remove
Ethernet will usually be handled automatically.


You can't for Ethernet, but can change it when you like.
For wireless, you would just need to delete the wireless profile. You will be asked what network location to use when you setup and connect to the wireless network again.