thumbnail linked to wrong source file

I moved a lot of files outside of LR and, as a result, have been busy correcting the links. When trying to reestablish a link for one particular file I selected the wrong source file. I got the "the file you have chosen has a different name...do you want to choose it anyway?" Without thinking I clicked "yes" and now I can't figure out how to correct the link. I don't want to go back to an earlier backup because, being an optimist, I kept correcting a number of additional links. Any help gratefully received. Thank you