Here you can see how I change the Date format of SharePoint list column.

• First add a new column  of Date and Time type(I named ExpiryDate) as follows:

• You can leave calculated value and Press OK.
• Then add another column so that new column can referenced by new one.I created(Expdate) column of calculated type as follows:

• Click on existing column from the DropDown and type the Formula:

=Text([ExpiryDate],"YYYY/DD/MM") or

=Text([ExpiryDate],"YYYY-DD-MM") and Click on OK.

See Format of ExpiryDate and ExpDate Column.