If you are a registered user, you can edit / remove any content you have personally added to the site by clicking on the pencil icon.
You cannot remove a notice from the site but should you wish to request for a notice you have placed to be taken offline you can use the contact us section to send this request.

Once you have made an amendment to a message, this will be checked by our moderation team again before being visible on the site, an email confirmation will then be sent when the message is live.