How to Launch REST trigger Agents in Agent studio from Smart Action in Fusion Service

I am trying to launch Attachment Processing agent and Service Request Summarisation agents which have REST trigger from Service Request smart action. DO I need to use UI based action or REST based action for launching this agent? If I use UI based action directly, the agents are not passed with additional arguments. If I use REST based action in smart action, it is giving error as "Child resource cannot be parameter". Please help me to solve this issue.