Changing the text that is being animated?

I'm trying to create a function that changes the text of the TextField that is being animated.
Whenever I change the text using fte.text = theText; it causes the effect to hang. Or Stop, or whatever. Visually, the text disappears.
I've tried to stop the effect and then restart it using
myEffect.stop();
fte.text = theText;
myEffect.show();
but that doesn't help.

Any ideas?
High level, I simply need to be able to change the text that's being animated after the animation has been started. It's fine (and preferable) to do it before the show effect starts.
Thanks in advance.
Bob