Hi @phoebe_90 you can do this multiple ways using a a formula such as Datatimeformat or the data time tool.
However I should add that Alteryx only recognises YYYY-MM-DD as a date format while you can transform your date in MM/DD/YYYY it will have to be or convert into a string field. Otherwise it be null if it was date data format.
There is a specific date time parse tool that makes this very easy. I suggest using that unless you have a good reason for using a formula.