For Pages installed from an iWork (no s) installation disk, use Software Update, the second item in the Apple menu on your Mac. Software Update will find and the updater will update the application only if it is in the iWork '09 folder, and that folder is in the Applications folder on your Mac.
The only ways to convert a file from AppleWorks to another format are to open it in AppleWorks, then Save as... in the desired format,
OR
to open the file in the application whose native format is the one you want, then Save it from that application.
Regards,
Barry