Help merging two references when both have been cited

Is there any way to merge two duplicate references into one so that I don’t lose the connection in the Microsoft word document? In other words, I have two references to the same exact work cited in multiple places in one document. I would like to merge the duplicates, and still have the microsoft word document reflect them.

Thanks for any advice!

In “Edit” menu, there is no the option of “preferences”…