Hopefully you’ll have figured this out by now but just in case, and for others that might be having the same problem (this was driving me mad on my Spanish site!), this is how you change it!
1. Go to Plugin Editor, select the plugin and open the file wp-customer-reviews/wp-customer-reviews.js.
2. Make a copy of the original code just in case.
3. Replace all instances of “Click here to hide form” with your text. It should come up four times (be careful not to delete any of the punctuation around this text).
