DFS3637 USER IN USE, CANNOT PROCESS COMMAND

Explanation
 The user referred to in the /ASSIGN command
cannot be reassigned because the user is signed on or is in conversation
mode, preset mode, or response mode.

System action
 The command is ignored.

Operator response
 Wait for the user to sign off or to terminate
conversation mode, preset mode, or response mode, and then try the /ASSIGN command
again.