How do I bring forward the background in a Voice Recording

I am new to this, but have an urgent need to attempt the following:-

I need to be able to listen to what is being said by others in the background of a recorded telephone conversation.

This would mean eliminating the main 2 voice conversation from the mono track and bringing forward and improving the background noise/conversation.

The file is .wav

The quality is fairly good and is in Mono

I am using Windows XP Op System

Anyone have any ideas?

Many thanks

Anyone have any ideas?

Yes, but not helpful. You can’t split apart voices in a mixed recording.