Scans designated as Baseline scans are retained until the baseline designation is cleared. If a Baseline scan that is in the Retained state has its Baseline status removed, that scan will be immediately marked for deletion.
Select Scans > Scan Data.
In the far left column, deselect the check box pertaining to the scan you want to clear as a Baseline scan.
Click Clear Baseline.
When the confirmation dialog box appears, click Yes.