My thesis uses someone else's template, but there is always something wrong with the header editor. Ask for help on how to modify a single header to make it different from other headers.
If the header of a single page needs to be different from other pages, you need to insert section break (next page) in the footer of the previous page and the footer of the current page, then double-click the header to enter the header editing mode, position the cursor on the header of the current page, and then click the Design tab to cancel the option of "Link to the previous page header". Similarly, position the cursor on the header of the next page and cancel "Link to the previous page header", then you can change the header of the current page, and other pages will not change accordingly.