The question is somewhat ambiguous.
1) If you mean in the animation editor, you can right click in the frames section and select "reverse frames". This will reverse the frame order of the animation.
2) If you mean at runtime, I am most certain that there is no native way as negative animation speeds won't work (still frame).
A possible, but tedious workaround is to copy the animation to be reversed, then reverse the frame order like explained in 1) and later, when exporting the project, make sure to select to deduplicate images. Like this you remove the identical images for both animation directions from the spritesheets and keep the file size and memory usage the same.