If you tried changing the format (Format|Cells|Number tab) and the display
didn't change, then the value in that cell isn't really a date--it's just plain
old text masquerading as a date.

If the "dates" are in a single column, you can convert that column by:

Select the column
Data|Text to columns
delimited (but remove any lines excel guessed and don't add any of your own)
choose dmy as the date type
and finish up that wizard.

Since the values are really dates, you can use format|cells to change the format
to the way you want.

ISO standered wrote:

i have huge data on this formate (different date) 13-08-2006. It can't change
of any other formate

--

Dave Peterson