I have a parent (Master Project) record with a subgird to show associated project records. When I click add new project, the lookup field on the project field gets automatically filled in (which is a 1:N relationship), so it is working correctly, however, now the need is to have that lookup field to be null only upon creation of record, so that the users can select a different value. As there is already another field capturing the parent record name. So if it is an existing record and something changes, no need to run the script to null the field.
How can I do this? I am guessing only with a script?