Hi Chetan,
It can be done by using custom Factbase attribute in your alert, for that you first need to create data collector class & custom FactGathering service.
Create you custom class and it should have interface IF_CRM_SMF_SERVICE or superclass as CL_CRM_SMF_ABSTRACT_SERVICE, redefine IF_CRM_SMF_SERVICE~Execute method.....here you have to write code to replace alert text and pass it to your custom factbase attribute (which you will create later) by calling method me->set_fb_attr_by_id
Create your custom FactGathering service using spro path crm->IC web->Addn Functions->Intent Driven Int.->Service Manager->Define Service, choose service type as Fact Gethering and enter the class created above.
Create factbase attribute (you must have already defined the name in you class where you set the value, use the same name) using spro path crm->IC webclient->Addn Functions->Intent-Driven Int->Define Repository. Now in the ICRULE context create new attribute, enter name description, select show attribute and enter FG service.
Now when you create your alert then select this custom Factbase attribute and it will show you custom value.
Hope it would be useful to proceed.
There is one article for similar enhancement by John Burton, but it requires paid subscription.
Regards,
Shobhit