UC telecom has requirement to allow customer to upgrade or downgrade from their existing plan...

The Change of Plan feature in Communication Cloud offers key capabilities including History of subscription updates and traceability (A), ensuring Service Continuity (C), and supporting Migrating in/out from bundle offers (D). These features enable customers to upgrade or downgrade their plans while maintaining service continuity and providing a clear history of changes for better customer management.References:Salesforce Communication Cloud documentation on subscription management and change of plan features.