You can create a Destroy Link Action through an Activity Diagram or a Modeler pane.
To create a destroy link action through an activity diagram:
1. On the Activity Diagram toolbar, click the arrow in the split button that is to the right of the Accept Event Action button, click the Destroy Link Action button, and then on the Activity Diagram, click in free space or within an Activity Partition, Interruptible Activity Region or Structured Activity Node.
2. From the Select Object dialog, select the Association that is to be the Linked Item, and then click OK.
3. Type the name of the Destroy Link Action, and then press the Enter key.
Modeler creates the Destroy Link Action and on it creates Input Pins for the start and end Roles of the linked Association.
To create a destroy link action through a Modeler pane:
1. In a Modeler pane, right-click the Activity or Structure Activity Node that is to own the Destroy Link Action, point to New, point to Action Node, and then click Destroy Link Action.
2. From the Select Object dialog, select the Association that is to be the Linked Item, and then click OK.
3. Type the name of the Destroy Link Action, and then press the Enter key.
Modeler creates the Destroy Link Action and on it creates Input Pins for the start and end Roles of the linked Association.
Accept Event Action button, click the 
Destroy Link Action button, and then on the Activity Diagram, click in free space or within an Activity Partition, Interruptible Activity Region or Structured Activity Node.