since this is the first thing that comes up in the search bar, and I had the same issue, I'll put a bit more details here on how to remove from jam without deleting your game, cus that's a mess.
click on the icon for your game jam submission and it will bring up your submission. on the left-hand side, underneath the name and the short description of your game, there is a 'edit this submission' and a 'remove this submission' button. click on remove this submission and done.