You can also highlight the reference mark (or footnote number) within the text which should bring up a dialog box that says, “Typing over a note reference mark will delete it and the corresponding footnote or endnote text. Do you want to delete the note or
change the options for how the marker is displayed?” If you click on the “Options…” button, it will bring you to the same options menu to change the numbering of the footnotes (but will change the reference mark at the same time). Probably the easier solution.