Step 1) Ensure that you are logged into your Facebook account.
Step 2) Login to GetYour.Reviews
Step 3) In GetYour.Reviews go to the 'Reviews' tab at the top.
It should default to 'All Reviews'.
Step 4) Find the review from Facebook.
It will have a Facebook logo in the far left column.
Step 5) Click on the 'Respond' button.
Step 6) You will be taken to Facebook and the review in question will be presented with a text box for you to reply.