Hi Prakash
transport collision for pfcg roles occur when a different role in the system you are moving the transport to has the same profile code
check table agr_prof or agr_1016 for role to profile mapping
parent role will not cause the conflict (unless it's profile is already assigned to another role). Suggesting to modify SAP standard for transports sounds like a bad idea! Parent role is transported for consistency as derived role gets it's menu from the parent as well as date/time statuses determine role authorisation status
Regards
Colleen