How does one update one file in a snap?

In the snap for application skanlite one configuration file /snap/skanlite/current/etc/sane.d/genesys.conf is either out-of-date or does not have the needed settings. How does one updated or override it?

In case the snap version is problematic, you can use the apt version. apt provides version 2.1.0.1 in Ubuntu 20.04.

sudo apt install skanlite

To update or reload the snap it is use the refresh option.

sudo snap refresh skanlite --edge

However, the above command may not update the skanlite application since it has not been updated since 2019-04-30

snap info skanlite
name:      skanlite
summary:   image scanner based on the KSane backend
publisher: KDE✓
store-url: https://snapcraft.io/skanlite
contact:   https://bugs.kde.org/enter_bug.cgi?product=neon&component=Snaps
license:   GPL-2.0+
description: |
  skanlite is a terminal based on an electronic game released in 1978
  Skanlite is a small and simple scanner application (based on KDE
  Frameworks) which allows easy scanning of images with an attached scanner.
  Through the KSane backend, it can access a wide variety of different
  scanner models.
snap-id: t44B2I4AeVBXO7Lbdg7pV9eN7JpvPq6w
channels:
  latest/stable:    –                                 
  latest/candidate: –                                 
  latest/beta:      –                                 
  latest/edge:      master+cb382f8 2019-04-30 (7) 9MB -