So this is how the hierarchy of the text property of a shape can be branched. You could substitute it with your actual variables for the application or the presentation or the slide.

So for example, if it were a variable with the name objPPT where you've got your application object, you could use
Code:
objPPT.Presentations(1).Slides(1).Shapes(1).TextFrame.TextRange.Characters.Text = "New Text"
or if you have objSlide as your slide object, then

Code:
objSlides.Shapes(1).TextFrame.TextRange.Characters.Text = "New Text"
Depends on how your code is written. But as you can see, the hierarchy of objects is the same.