Date change [Closed]

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The interfaced data date from an EMR system to my system reported as an Excel has the date with Year, month and date, example 2017-01-15. I am trying to change the date format to month, day, year example 1/15/2017. I can change cell by cell but I can not do duplicates or a column at a time. I need to do this as a whole column. Thanks!