We have a scenario where if user selects an option to install rpm (choice parameter) then display an additional field for user to provide input rpm package info in Jenkins UI.

 Please see Input text box disabled.png and Install input text box field.png for reference.
 

If user selects option as rollback (choice parameter) then don't  display any additional parameters in Jenkins UI.

Please see Rollback still displays input text box field.png for reference.

Note:- "RPM_Package_Action" is an active choice reactive reference parameter
"packagenames" is an active choice parameter

Let me know if any additional information is required.

Thanks,
Pavan.