For Quickbooks 2019 Pro

1. Click on Home
2. Click on Reports (in left menu list)
3. Click on the Memorized tab (above the list of reports)
4. Click on the Edit Memorized List (it has a pencil next to it and is to the Right of the tabs group
5. Right Click on the report you want to delete
6. Select Delete Memorized Report
7. Click OK to confirm deletion

Hope that helps!