Comments Plus question

Could someone please let me know where to change the length or name of the title in comments plus for the wordpress portion without affecting the rest of the site?

For example, if the site name is

mybestsite.com and the tagline is What a Great site This is then
for the wordpress comment plus tag option I am seeing the tagline which is too long of a string of text for the area below where it says Click on a tab to select how you'd like to leave your comment, and what I would like to appear is the site name, not the tagline. Is there a place to change this?