To modify the keywords within an existing campaign, there is no need to initiate a new campaign. Please follow these steps for adjustments within the Marketing Center:

1. Navigate to the "Campaigns" tab.
2. Locate the campaign you wish to amend and select the “View” link adjacent to it.
3. Proceed to the "Target Audience" section and click on “View”.
4. In the Keywords section, select the “Edit Keywords” button to make necessary changes.
5. To access the list of keywords, click on the category names. At the top of this section, you will find an “Add New” button, which enables the insertion of additional keywords.
6. To remove any keyword, use the “Remove” button located next to each keyword.

This process ensures precise and efficient management of your campaign's keyword strategy within the Marketing Center.