If you want to change the direction of a connector, you do so by adding a new arrow to the end without an arrow and removing the existing arrow from the other end.
You can add, change, or remove arrows from a connector by using the following procedure.
To change the direction of a connector by changing the arrows on the ends of the connector
Select the connector that you want to change.
On the Home tab, in the Shape Styles group, click Line, and then point to Arrows to open the Arrows menu.
At the bottom of the Arrows menu, click More Arrows.
Visio displays the Format Shape task pane with Line expanded.
To add, change, or remove an arrow on the beginning of the selected connector, select an arrow or None on the arrow menu for Begin Arrow type.
The arrow menus show the currently selected arrow style or None for the selected connector.
To add, change, or remove an arrow on the end of the selected connector, select an arrow or None on the arrow menu for End Arrow type.