How Do I Get Rid Of Milliseconds From A Whole Column Of Data In Excel

12:32:01:.6240

12:32:01:.6339

12:32:01:.7249

12:32:02:.7259

And there is another column in another spreadsheet that I need to compare the time stamps to, but it does not have the milliseconds. It just looks like this:

8:00:51

9:02:06

9:20:26

I have tried writing a macro, everything I know how to do, but I can’t get it to change the whole column. It puts PM in the formula bar. It only changes one at a time. And there is 23K+ rows of data, so I can’t do it one by one. Please help!

Thanks,

Kim