The solution and specific operation steps are as follows:

1. Step 1: Open Word, put the cursor in the directory, and the directory background turns gray, as shown below, and enter the following steps.

2. Step 2: After completing the above operations, click the "Update Directory" button in the menu bar above, as shown below, and enter the following steps.

3. Step 3: After the above operations are completed, in the pop-up dialog box, select the option of Update Page Number Only, and click OK, as shown below, to enter the following steps.

4. Step 4: After the above operations, the table of contents has been updated, only the page number of the table of contents has been updated, and the table of contents format has not changed, as shown in the following figure. In this way, the problem is solved.