If I need to change the description on two of the sessions I have uploaded and are now showing on the site, do I just make the changes and re-submit themto Auran under the same KUID for approval?
You may need to update the version part of the KUID (for example, if your KUID was <kuid:12345:12345>, you would need to change it to <kuid2:12345:12345:1>
Basically, it's creating a new version of an asset without changing the main part of the KUID.
You can right-click an asset, and click Create New Version to update the version - all you then need to do is commit that version (which will be the version you edit/upload etc)
It will automatically obsolete the previous version of the session.