How to change file extension without having the program itself?

if i have a .docx file (for example), how can I change it to .doc file if I don't have Microsoft Word 2007? So i can open it on microsoft Word 2003?

Thanks for any help!
How to change file extension without having the program itself?
Downloading and installing the free Microsoft Compatibility Pack on the Word 2003 machine will permit Word 2003 to read and write the .docx files. Note, though, that some Word 2007 stuff will be converted to straight text.



Changing a file extension has no effect on the contents.



Hope that helps.
How to change file extension without having the program itself?
You can't rename the file and get it to work on an older version of Word. You could try the Microsoft Office Compatibility Pack for 2007 Office Word, Excel and PowerPoint File Formats. By using the Compatibility Pack for the 2007 Office system, you can open, edit some items, and save Office Word 2007 documents in previous versions of Word.



Go to the link below for mire info



http://office.microsoft.com/en-us/word/ha100444731033.aspx
If you don't have the program you can convert it online at http://www.convert-doc.com or http://www.docx2doc.com or http://www.oconvert.com