Modifying existing attributes. Calling Center - Manager
When we created our attributes using the Attribute Creation Wizard, we specified that all attributes had 1:M relationships. However, this is not true. Calling Center and Manager have 1:1 type of relationships, as each Center might have only one Manager, and one Manager can manage only one Calling Center.
Double click on your Manager attribute and click on Children Tab. Change relationships from One-To-Many to One-To-One.