It depends on exactly what's wrong.  If it's a factual thing like someone's height, age, or website or phone number, or anything like that, the easiest way to fix it is to click on the link "Problem Report" on the profile page and submit the correction.

If what's wrong is the list of services, that's a little harder to change.  The staff take the view (and IMHO rightly so) that what a guy says was offered should take precedence over what an agency *thinks* the girl offers.  Let's face it - there are many girls out there (and agencies representing them) that claim they are GFE but really aren't.  There can be many other differences and, well, money talks.  The agency may think a girl doesn't do greek but if a guy is in the hotel room with her and offers her enough money, she just might and the agency wouldn't know.  So, getting information like this changed is much harder because the staff leans on the side of the hobbyist.  But, if you want try, you can use the "Problem Report" method.  If you don't get results that way, you can try the "Contact Us" link at the top of the page.  But, whichever method you use, make sure you can make a good case for why the info is wrong or else the reviewer staff will just ignore it.  Sometimes, it's easier to get the guy who wrote the review to make the correction.  

One word of caution: Usually, any response you get comes to you via the Account Manager.  You can got to "My Feedback" and/or "My Problem Reports" and find the response there.  "My Feedback" is where you'll find answers if you use the "Contact Us" link.  "My Problem Reports" will hold the responses if you submit a Problem Report.  Sometimes you'll get email notification that a response has been posted, sometimes not.  So, after you submit your correction, wait two days and then start looking at "My Feedback" or "My Problem Reports".

Changing the description of the date, the details, the "story" as it were, is damn near impossible.  No one but the guy and the escort knows what went on in the room.  And, since the reviews are a work of fiction anyway, the writer will almost alway win.  The only way that part can be changed is to prove to the Powers That Be that the entire review is fake.  Good luck with that.  I'm not saying it's impossible but it's not easy.  And, if it's the only review for that provider/agency, and TER suspects that there is fraud involved such as that hobbyist never saw that provider... well, one or the other (and possibly the agency) could end up being banned.  

Disclaimer: I am a moderator on the discussion boards.  As a moderator, I have NOTHING to do with the reviews section.  I'm not even allowed to post a review.  My comments above come from my experiences as a hobbyist and having posted reviews in the past, and from hearing stories from providers about incorrect profiles and reviews.  In no way do I speak for the management of TER or the review staff.  My opinions are just that: mine.  And you can't have them.