It's possible to reconnect a group to a different VPN server without first disconnecting your current VPN connection.
This is a security measure aimed to prevent data leak when you want to switch to a new server or provider. This way no routing happens over your normal ISP connection.
Go to Menu ➝ Devices
Locate the Change location link in the header of the group and click it
Select the VPN provider and region you want to connect to and click Reconnect
A spinning circle will appear for a few seconds, and once the connection has completed successfully you will see the notice 'Connection to VPN server established' pop up.
Note! If the VPN connection you are switching to fails for any reason, there won't be any leaks as Vilfo switches back to the initial VPN connection safely.