You can add an existing segment to a campaign by selecting it in the Segment Picker as described in the previous section. You can then make changes to it as required. Bear in mind, however, that any changes you make to an existing segment are saved as a new version of the segment, which then becomes the version used by other campaigns. In other words, the changes are not made exclusively for the current campaign. Any other campaign that is being edited, as well as any campaigns created in the future, will see the new version of the segment. If you do not want the changes used elsewhere, create a new segment rather than editing one that exists already.