To clear the lookup settings, delete the Lookup field. Even if you delete the lookup field, values in other fields for the entered record do not change.

To delete a Lookup field, use the following steps:

1. Access the settings page of an app from which you want to delete a Lookup field.
   Opening the "App Settings" Screen

2. Ensure that you are on the "Form" tab.

3. Hover the mouse pointer over the Lookup field to delete, and then from the gear menu, click Delete.
   

4. If the confirmation screen opens, click Delete.

5. Click Save Form on the upper left side of the screen.

6. Click Update App on the upper right side of the screen.

7. On the confirmation dialog, click Update App.