If your GitHub profile is integrated with SOOS, you can run a GitHub QuickScan against any of your public or private repositories at any time, without needing to make a commit.  Read more about GitHub Quickscan.
SOOS UI QuickScan option

A second option is to upload a manifest and scan as-needed using the Manifest Scan option.  Manifest Scan results will generate a new project on the home dashboard; the project will be named to align with the name included in the manifest file.  Read more about Manifest Scans.

SOOS UI Manifest scan option

Another feature SOOS has available is the Rescan Now option on the Project Details page.  This feature lets you instantly refresh the vulnerability data from your most recent scan for your project from within the SOOS UI, without needing to re-upload the manifest or reinitiate a GitHub QuickScan.