write one script in python and create new csv file for the date format:

suppose you have customer csv open it using below code and format date as per requirement I had split the date with . (dot) you have to format the code as per your requirement.

from new csv file copy whole column to the original csv file you get the formatted date as per requirement.

import csv
csv_rd = csv.reader(open("customer"+".csv"), delimiter=';')
count = 0
for rec in csv_rd:
    fields = rec
    break
all_datas = []
for rec in csv_rd:
    all_datas.append(rec)
a = []
for rec in all_datas:
    print rec[7]
    print rec[7].split('.')
    s = rec[7].split('.')[2] + '-' + rec[7].split('.')[1] + '-' + rec[7].split('.')[0]
    print s
    a.append(s)
with open('eggs.csv', 'wb') as csvfile:
    spamwriter = csv.writer(
        csvfile, delimiter=' ', quotechar='|', quoting=csv.QUOTE_MINIMAL)
    for val in a:
        spamwriter.writerow([val])