On the appointment overview shown on the right side after selecting the desired appointment, click on "Actions" and select "Manage recurring service" from its drop-down.

Once taken to the "Manage Recurring Service" page, click on the "Change Default Status.." button underneath the Default Appointment Information section.

On the pop-up window, expand the drop-down menu under the "Change status to" field.

Select your desired status.

Afterward, click on the appointment shown underneath that you'd want to change the status.

Note that the status will only change on and after the date that you've selected.

Click the "Change status after the service selected above" button to save your changes.