If you created an Input Position Locator when you created the closest point constraint, you can adjust the position of the locator using the Move tool.
The closest point locator (if you created one) and the result calculation are updated accordingly. (See View closest point constraint result.)
If you did not create an Input Position Locator as you created the constraint, you can manually define the input position using the constraint’s In Position attribute.
To manually set the input position
This defines a new input position, and the closest point result calculation is updated accordingly. (See View closest point constraint result.)