HI Rao,
To achieve this we have introduced "Conditional User Input" feature in 2.1.
1) Go to, workflow edit-> Settings -> User Inputs Tab,
2) For "Size" user input(open it by double-click), in Dependency section, choose user-input "Action" from drop-down list
3) In applicable values, mention Create
4) follow the same procedure for guarantee/aggregate name user-inputs too.
5) Save the workflow, when you do preview/execute these fields will be enabled only for "Create" Action.
Warm Regards
Sivaprasad K