Can i modify the line path in Text on Path?

Hi guys,

Can i modify the line path shape in Text on Path? Like if i were modifying a regular stroke path.

I want to extend the line or path to change it curve so my text do not overflow. I would like to make the text longer but with the same size. So next to edit the line not the text. I find that when ever i click the Selection (black arrow) or Direct Selection (white arrow) tool i cannot tweak the line path just the text. Maybe this is very easy to do but i cannot figure it out.

Here is a sample

Thanks!