I would suggest you raising the SR for this, as there is no straight forward way to delete the Campaigns, you might have to delete from the Database. GCS can provide the SQLs based on the campaign management data
By default Chordiant Marketing Director (CMD) application does not allow to delete the campaigns if the current status of the campaigns are in 'Decomposing' state. It needs to be manually changed to 'Approved' state by running the following SQL in database:
SQL>update camp_status_hist set status_setting_id=15 where status_setting_id=14 and camp_id=<campaign id>;
After this, the campaign will change to Approved state. Next, change the state of this campaign to 'Defined' by opening this campaign from Campaign Builder module and choosing the 'Define Campaign' option. On performing these operations, the delete button gets enabled at the campaign level.