To change how an audience is targeted, you’ll need to edit the audience.
On the Campaign Overview page, drill down into the campaign for which you’d like to edit an existing audience by clicking on the campaign card in the campaign list.
On the Campaign Details page, for the audience that you want to edit, click on the pencil icon that is in the "Actions" column.
The audience wizard will appear, and you will be able to edit the audience targeting. The audience wizard experience is identical to creating a new audience, except the wizard will be pre-populated with the audience’s current targeting. You can jump forward/backward to any step in the wizard to edit targeting criteria as need be.
Once all you’ve made all the necessary edits to your audience, click “Save".