angle dimensioning between two parts in assembly

Hello,

I have made an assembly of a flap and a wing of an aircraft. the flap is mated with the wing using two points, one on a flap and other on a wing. I want to give the angle dimension between the constrction line on a wing and the construction line on a flap. Both the construction lines are coincident with the points used for mate. I used the smart dimension in the sketch mode of assembly but the angle so created is just an annotation (cannot be altered). Is there any way this dimension becomes active (changeable)?

SolidworksAssemblies