Changing font color of another movie clip's dynamic text (probably ridiculously easy)

programming flash
1

Hi guys - I have two movie clips on the stage - KRS_ZOOM and heading_mc.

heading_mc contains a dynamic text box named ht. I am trying to change its font color via a frame on the KRS_ZOOM movie clip. how can i reference it?
My code below is not working.

tf = new TextFormat();
tf.color=0xFFFFFF;
trace(_root.heading_mc.ht.text);
_root.heading_mc.ht.setTextFormat(tf);

2

In frame 1 of KRS_ZOOM:
_root.heading_mc.ht.textColor = 0xFFFFFF;

In frame 10 of KRS_ZOOM:
_root.heading_mc.ht.textColor = 0x00FF00;