Hello Mridul ,
Defining Operation Modes
http://help.sap.com/saphelp_nw70/helpdata/en/c4/3a5f2c505211d189550000e829fbbd/frameset.htm
Central auto-reaction methods can be created by using the transaction
function "RZ21>Technical Infrastructure>Configure Central System>Assign
Central Auto-reactions"
To configure auto reaction methodes please check:
Setting Up Central Auto-Reaction Methods
http://help.sap.com/saphelp_nw70/helpdata/en/ac/825f18c02e454dac8da51f4eb22265/frameset.htm
Please have a look at in notes too:
1636899 - Setting up CCMS Auto-Reactions, and Analysing Issues
176492 - Automatic email when an alert occurs (RZ20)
939616 - CCMS auto-reactions: Help with troubleshooting
BR
Tamas