I have turned my Figma design file into a FigJam file. How do I revert?

Hi,
I have somehow turned my Figma design file into a FigJam file, where I have now have a set of comments and replies. How do I revert this FigJam file back to a design file and keep the comments? IE I do not want to copy and pasting !

There did seem to be a bug of some kind during the process of initially converting designs to FigJam…

Thanks,

Jim