Hi,
Assuming the date you want to convert is in cell A1, and the format of that date is 'yy/mm/dd', and also your computer's regional setting is US, ie your date would be mm/dd/yy.
Then, the following formula might help you:
=date(left(a1,2),mid(a1,4,2),right(a1,2))
The above date is formula is based on =date(year,month,date), so you can adjust the length of your substring.
HTH