Material libraries can not be edited once defined. If a material was created to work with lots there is no option to remove the requirement.
Solution: Create a custom material library without lots.
Steps:
1. Log into Signals Notebook as an administrator
2. Navigate to Signals Configuration > Materials
3. Click 'Create Material Type'
4. In the 'Type' dropdown menu select 'Custom'
5. Fill the 'Material Type Name' and 'Asset Level Name' as needed
6. Remove the checkmark from the 'With batches/lots' option
7. Click 'Create'