how to unlock a word document?

Can anyone let me know how can i unlock a word document? I have followed some articles regrading the same but i am not able to Expand Subdocument as things on tool bar are inactive. Is there anything i can try for activating the options on toolbar and unlock word document?

Any help would be grateful, thanks in advance.

What exactly you are trying to unlock ?

Which version of MS office you have installed??

Which article you have followed??

Just answer all of the above questions so that i can have better idea of the issue you are going through.