heres what you can do
in another blueprint in your game, you will create a dynamic material instance of this material, then you can get specific parameters from it. (in this case, the variable is the myVar1 scalar parameter.) if this variable is >= 1, it will pan the texture, if it is < 1, the panner wont do anything. In that blueprint where you are setting myVar1, you can use delays to control how long the panner pans for.