Guide provides you detailed step by step information required to move a mailbox from on-premises exchange to exchange online in cloud and back to on-premises via online exchange admin center and powershell . Steps included in the guide have been defined as per best practices used in hybrid exchnage environment across several organizations around the globe .Domain names and servers used in guide are solely a part of test lab environment and does not points to any public or private organization's server in real world. Happy learning. Human knowledge belongs to the world .