I have an issue in Excel I am hoping someone can help me with! In spreadsheet I, I have two columns of data, call them A and B (about 17,000 rows). A and B are related in a way that they are two different identifiers for the same thing. In spreadsheet II, I have just a portion of the rows of Column A (about 9,000 rows). I need to replace the data in Spreadsheet II, Column A with the data from Spreadsheet I, Column B, ensuring that the relationship maintains. Does this make sense? Basically, I am switching which product ID codes I am using in an inventory spreadsheet but I have to make sure I replace the existing codes with the exact new ones. Thanks a million!