A migration from an on-premises system to a cloud-based one is an enormous project that typically takes anywhere from 6 to 18 months. The length of the migration is dependent on a number of factors, including: the complexity of integrations into the existing system, whether or not APIs exist, the complexity of connecting to the CRM, the size of the contact center, whether the current system is also the phone system for other parts of the business, the level of customization built into the existing system, the number of and types of functional improvements that are sought after during the migration, and whether the company will manage the RFP process alone or will use an external consultant.