Sounds simple: Exchange cells in Excel. And actually it is. Here is what to regard in you a) want to exchange all references as well or b) keep the references as they are when you swap two cells.
Data Validation in Excel: Restrict Cells to Allow Only Certain Values
Working with other people on the same Excel file can be challenging. Especially when you prepare an Excel workbook and another person has to fill in some data. In such case, you probably want to make sure that only your intended values are possible to enter.