I have a pivot table that contains a data and two data values. the date has been formatted as 'ddd dd-mmm'

Date | Value 1 | Value 2
Wed 26-Nov | 23 | 85
Thu 27-Nov | 17 | 85
Fri 28-Nov | 17 | 80
Mon 01-Dec | 12 | 80
Tue 02-Dec | 18 | 100
Wed 03-Dec | 30 | 120

When I create a Chart the data table shows the date in the original format, e.g. 26-11-2014 (UK date format).

Is there a way to change the format of the date in the data table so it is Wed 26-Nov?

Have it as a text field?