Is Updated or Is Changed Modifier

Hi Fusion Community,

I'm doing an API call with a Fusion module, which is new learning for me, and I'm trying to determine if there's a modifier I can use to determine when a field value changes (is modified or updated)?  Curious what I can use in the Value field for the plannedStartDate_Mod, as shown below?

Ignore the blue squiggly part, I'm just testing...

Thanks,
Nick