This is how to save a Favorite Stitch (FS)
Select the stitch
open the adjust Screen
make the changes
select the button with the black arrow pointing down into a folder
you can save it as either FS1 or FS2
choose one of them
the screen goes back to the adjust screen and now you’ll notice that the stitch settings are pale yellow where you made the changes
you don’t need to sew it for the settings to set
next time you select the stitch it will open with the FS adjustments
If you want it to temporarily go back to the original Default settings, just select the DFT button and it will, and it won’t delete your FS.
To delete the FS:
open the adjust screen
touch the trash can
screen opens for the FS1 and FS2
select the one you want to trash, it trashes the settings and goes back to stitch in its default size.