With the database whose relationships you want to edit displayed onscreen, click the Relationships button on the Standard toolbar in the main Access window.
To change the relationship options, double-click the relationship line.
The Edit Relationships dialog box opens. Make changes as needed and click OK.
Click the Save button on the Standard toolbar in the main Access window to save the changes.
After you have established a relationship between tables, you may need to make changes. For example, you might decide to change the options for how the relationship works, or you might want to delete the relationship.
To delete a relationship, click the relationship line to select it and press the Delete key on your keyboard.