Hi @ChristyCool,
It sounds like you're trying to set things up in an old course shell before the next year's course is made available to you. Am I correct in that assumption? If so, the issue is probably that your school locks down courses once the term/year is over. In most cases, you'd do adjustments like this when your new Canvas course site becomes available. When you use the import tool to get content from a different course into the new one, there will be a date adjustment or removal option as part of the process. That's probably going to be the way to go for a task like this. You could reach out to your local Canvas team (usually in the eLearning / IT / Digital Education areas) to find out when next year's course will be available to you.
Hope this helps a bit!
-Chris