Switch from Incident to Service Request
In creating a Progressive capture for an Incident, you might want to branch from one Progressive Capture to another as outlined on https://wiki.hornbill.com/index.php/Switch_Between_Progressive_Captures or you might wish to Switch Call Classes from Incident to Service Request. For example, a customer may be raising an Incident using the portal and if they choose an answer, it continues being an Incident but if they choose another option it becomes a Service Request. A Switch Node in the Progressive Capture would not work because an Incident and Service Request need to have different Business Processes.
Customer raising either Incident or Service Request
In such a scenario, it would be best to use the catalog items against the services. For the Incident, use one Service and catalog Item pertaining to Incidents and for the Service Request, use either the same service and a different catalog item or another service altogether. It all depends on the configuration you choose in the Service.
One service can have a Catalog Item specifically for raising Incidents.
The same service can have a Catalog Item that can be used for raising Service Requests.
So depending on the customer's issue they can either use one catalog item or the other to raise either an Incident or Service Request.