A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Here is a procedure to re-format the dates that you want to change.
- Select all of the dates that need to be changed.
- On the Data ribbon in the Data Tools section, select Text to Columns.
- In the Convert Text window leave the first screen on Delimited and click Next, and on the second screen leave Tab selected and click Next.
- On the third screen choose Date and, in the dropdown, choose DMY. Then click Finish.
That will re-enter the dates as number values and formatted the way you want.