Here's one way of doing it:

As root, while no other users are logged in, no user processes are running, and user cron jobs and systemd timers (if any) are disabled (in short, when there's no chance of user files/dirs being modified while the `mv` operation is in progress):

```
mkdir /home.new
shopt -s dotglob nullglob # make sure dot files match the /home/* glob
mv /home/* /home.new/
umount /home
rmdir /home
mv /home.new /home
```

(you can use `mv -v` if you want verbose output so you have something to watch while the files are being moved - but note that verbose output will cause the move to be significantly slower).

Then modify `/etc/fstab` so that it doesn't mount the old home partition.
You can do that manually with your favourite text editor, or with a program like `sed`, e.g.:

 sed -i 's/^UUID=6397f416-fe69-4a90-9336-7497d42df184/#&/' /etc/fstab


Note: a safer alternative would be to use `rsync` to copy all the files from `/home` to `/home.new` rather than `mv` them. That eliminates the risk of losing any files if something unfortunate happens (e.g. sudden crash or power loss). Then either delete all files in the old /home or reformat the partition after everything has been copied.

Using `rsync` also reduces, if not eliminates, the risk of problems caused by user files/dirs being modified during the procedure, as you can re-run the `rsync` command as many times as you like and only new/modified files will be synced. Do the initial `rsync` at any time, and then do a final `rsync` when nobody else is logged in. The final rsync will be very fast, so that will minimise downtime for users.