Available in: DESelect Segment Enable, DESelect Segment Plus, and DESelect Segment Advanced
If you are wondering for a better way of simply changing the relations of your Selected Data Extensions, then read up!
Let's say you have created the below relationships and realized that instead of combining DESelect_DEMO_Orders with DESelect_DEMO_Customers, it will make more sense for the selection that you are creating to combine DESelect_DEMO_Orders with DESelect_DEMO_Contacts.
You can surely just remove the relation between DESelect_DEMO_Customers with DESelect_DEMO_Orders by removing the DESelect_DEMO_Orders Data Extension and adding it again to define the relation with DESelect_DEMO_Contacts. However, there is an underlying additional step if you have used the fields from DESelect_DEMO_Orders either for filters or mapping in the Target Data Extension, you'll first need to delete those and then delete the relationship.
Instead of deleting filters and relationships, you can redefine the relation by dragging and dropping the DESelect_DEMO_Orders from its current place on top of the DESelect_DEMO_Contacts Data Extension, and you will be asked to choose the Matching Field and Mach Type for the new relation. Don't worry about the unnecessary relations as those will be deleted automatically.