I can help you with this. Select the column/row that you need to reformat.
Go to the Data Tab
From the Data tab, Select Text to Columns
This will open a Wizard called "Covert Text to Columns"
You'll see 2 choices for your original data type: Delimited or Fixed Width
If your current date format has commas, tabs, dashes, etc., then click Delimited.
If your current date format has only spaces separating everything but no characters, then click Fixed.
Click NEXT once you selected your origiinal data type
The next screen, you can skip by clicking NEXT again
Now you'll see a screen that lets you slect the data format that you want
Select the DATE button
Then, from the drop down, select the new date format you want to use.
This should do the trick. I hope this helps!!