Ah, that changes things a little of course.
In order to cast to your input widget you need to create a variable for it when you draw it. Where you cast to depends on where you draw the widget. Assuming you draw it in your character blueprint, it could look something like this:
In your output widget, create your text block in the designer tab. In the details panel, create a binding for the text content and open it via the magnifying glass icon or the graph tab. Here you can cast to your input widget and access your text variable like this:
Of course things might need to be changed up a little depending on your setup, but hopefully this will get you going. 