Is there a way to change, edit, or delete an end of survey message once it is created? I had to make a slight adjustment and I had to create a whole new message?

@wilpr74You can navigate to the Library→End of Survey Message and then you can edit it.Hope it helps!

If you will navigate at the end of the survey and click on the end of survey block you can create a new custom message or can be done through end of survey block in survey block.