If a client has numbers in their columns and rows here is how to change it back to A1 prefix style
R1C1 reference style is an alternative to the A1 reference style. In R1C1, rows and columns are numbered instead of using letters for columns. Follow the next few steps to change back to traditional A1,A2,... Style.
Step 1: Begin by opening Excel and navigate to the File menu located in the upper left corner of the application.
Step 2: From the File menu, select Options in the bottom left corner of your screen. This action will open a new dialog box where you can customize various settings in Excel.
Step 3: In the Excel Options dialog box, look for the Formulas category on the left-hand side. Click on it to access the relevant settings.
Step 4: Within the Formulas section, you will find a subsection labeled Working with formulas. Here, locate the checkbox that is marked R1C1 reference style. Uncheck this box to disable the R1C1 reference format.
Step 5: Finally, click OK to confirm your changes and close the dialog box. Your Excel will now revert to using the A1 reference style.