'Being from out of town, I found your service to be excellent.'
'Delivery was at martini time - a request I had asked. Thank you so much. The beautiful flowers and smiley face gave great cheer to my dear friend Nancy.'
'Thank you all again for your help and support. The link was excellent and so easy to view the arrangements. It truly helps when you are so far away.'
You won't be able to dismiss this by usual means (escape or click button), but you can close it programatically based on user choices or actions.