Data Migration for Data Center Operations

My company was informed that a major vendor will not support its Mainframe application in two years with a third year extention. We're currently running two systems. One is a leagcy system (Test/Prod)z/os and Oracle (Test/Prod.
What was the role of the Computer Operations Dept. at your company during your migration from Mainframe to Network processing? Where can I find info on the human cost of migration? Training, attrition, lay-offs, promotions, new job descriptions etc.