CRM Contract Cancel Bapi/Method

Dear Experts,

I'm trying to cancel a contract through a specific z button in view BT126H_APPT/ApptOVViewset. I've created the button and created the event that is already called.

The question is regarding the cancel process. I was going to use the following class CL_CRM_IU_PR_CNTR_END_HD, but indeed in method start it should pass a context of type IF_CRM_IU_PROCES_CTXT that i'm unable to get it.

I believe that the process cancelation should be called by a process, maybe by the process manager, but how can i do this?

Can you help me how can i get this context or use a BAPI, i saw BAPI_BUSPROCESSND_CREATEMULTI. Is this possible through this BAPI?

Thanks.