How to Replace Duplicate Letters in Excel. Using the find and replace ability in Microsoft Excel 2010, you can quickly replace duplicate letters, words and cells in a spreadsheet document of any size.

Press the "Caps Lock" key on the keyboard. Type the first instance of all capital letters to change into the Find What text field. Type the preferred capitalization into the Replace With text field.

You can search in Excel with the Search Sheet bar, and use Find and Replace to swap out terms or values. Here's how to do it.