The best way for you to do this is to save a copy of the file and label it with a date for next week.  Then you can work from what you did last week in a separate version without loosing the prior week. 

If you liked a meal prep from a certain week or period, such as a bulk phase or lean out phase, then you can go back to these in the future as well to save time.  When you save the version, give it name that might hint to you what that plan was like.