Hello,
Without re-recording you will need to either compress the file in a zip folder or so which might help a bit, if not you might want to consider a file converter to covert the file to a format that does not create such a large file size and the converter might have the option to lower the quality of the file to get a smaller file size as well.
NCH Offers a great converter called Prism, you can learn more about it on the link: https://www.nchsoftware.com/prism/index.html
Good luck!