If it is the same as with the Existing Find My Phone 1. Resell - you turn off 'Find My' on your phone and sign out of iCloud then wipe the device 2. Loss - Go

If it is the same as with the Existing Find My Phone 1. Resell - you turn off 'Find My' on your phone and sign out of iCloud then wipe the device 2. Loss - Go into iCloud and mark the device as lost. Not sure what this means for finding other devices 3. New companion device - sign it into iCloud.