The following steps are applicable if you have the Microsoft Mail Connector installed on Server A.
To move the Microsoft Mail Connector
Run the Microsoft Exchange Administrator program for Server A, noting the settings for the Microsoft Mail Connector.
On Server A, stop the Microsoft Mail Connector Interchange, any Microsoft Mail PCMTA services, and the Directory Synchronization service.
Make sure that the Microsoft Mail Connector is installed on Server B. If it isn't, install it.
On Server B, configure the Microsoft Mail Connector exactly as it was configured on Server A.