I already tried to merge them, but then I realized that this is not accurate since both of them represent the exactly same edition. So then I've split them again. Now both of them have all the reviews which is fine since this is what you would like if one of them is being removed.
Merging is the correct process. Combining them and then deleting one of them is the only way to preserve reviews. So I have recombined them and will delete one.
I already tried to merge them, but then I realized that this is not accurate since both of them represent the exactly same edition. So then I've split them again. Now both of them have all the reviews which is fine since this is what you would like if one of them is being removed.
Thanks.