I have created aletrs in splunk. Now I want to generate tickets on basis of that alerts in a ticketing tool like BMC using Rest API.
Can yout suggest me guidelines to do so?
There is no out of the box feature that lets you do this.
However, If you have a script that can create tickets in BMC, You can have your splunk alert call that python script when the alert triggers.
Starting 6.3 you can use custom alert actions, only if there is an app already that interacts with the ticketing tool you want. More information in the link below
http://docs.splunk.com/Documentation/Splunk/6.3.3/AdvancedDev/ModAlertsIntro