It should not be a common occurrence that services are deleted in WP. Depending on how far you are into the planning process, you may not be able to delete a service.  If anyone has been schedule for a service and their status is Pending, Tentative, or Accepted, you will not be able to delete that service.  You will first have to delete those assignments. 

To delete a service, hover on the Services navigation link, then click the Manage All Services menu option. Find the service you'd like to delete, then click the Delete icon ("X") next to the service you'd like to delete. You will then be prompted to confirm the deleting of the service.

If the service you are trying to delete has services linked to it, you will not be able to do so. You will first have to delete the linked service before you can delete the master service.

When services are deleted, files associated with the service are NOT deleted. Only the association of the file to the service is removed.

Currently, WP does not support deleting multiple services at a time.