Customer is looking for the ability to search and select existing contacts and add them to the sub grid within the Account Entity. Currently the system just opens the quick create form when the customer clicks +. Workaround solution to change the out of the box relationship account_primary_contact to optional instead of required. Even though you can change the Field requirement it doesn't change the functionality of the sub grid like it should.

This is the same for the searching and selecting existing Cases always opens quick create window even with relationship is optional.

Can you please allow the relationship to be edited to facilitate the ability to "Add Existing" Contacts/Cases from the sub grid using out of the box relationships.