How to protect and unprotect worksheet

[ballack]

Hi,
I have three worksheets in my Excel,

Inside a macro,I want to unprotect all the three worksheets , do some functions and protect all the sheets again.

How can i do it?

I tried

    Sheets("PRODUCT_DETAILS").Unprotect = True
    Sheets("PRODUCT_PRICE").Unprotect = True
    Sheets("PRODUCT_RELATION").Unprotect = True

But its not working.