You require Avaya Aura® Device Services to search for corporate contacts in Avaya Aura®, Avaya Experience Platform™ On-Prem, and enterprise directory sources to transfer or consult. Without Avaya Aura® Device Services, the agent needs to know the number to transfer the call. This applies even if the number to transfer the call belongs to another Avaya Experience Platform™ (On-Prem + Connect) agent. Hence, you must configure Avaya Experience Platform™ (On-Prem + Connect) with Avaya Aura® Device Services for an optimal agent experience.