How update a date column into another format?

Question

Hi,

I have a table column Plaerdob witch have diff date type like

1- 1-jan-1987.

2- 01/01/1987

3- 01-jan-1987.

Here i want to update all my dates format of 2 and 3 into 1.

Can it be possible? if yes then how?

Pls help.

Thanks