You have 30 days from posting feedback to remove it and post new feedback. Please take the following steps to modify feedback:
Visit the Problem
tab and click on Problem with Feedback
. Make sure the radio button for "Feedback I posted" is selected and enter the Order ID, then click "Submit Request". You should receive a message stating the feedback for this order has successfully been removed.
You will now have to re-post the feedback for this order. To do this, simply visit the My Orders Placed
tab and click on "Post" next to the order he wishes to leave feedback for again.