How to pass Parameter values as Boundaries to the correlation function in loadrunner

When you want to pass the user defined parameter as left or right boundaries, you can directly pass the parameter as boundary values. In the below screenshot you can see that P_Server is the user defined parameter and it has been directly passed as the Left Boundary.

When you want to pass the Correlation parameter as left or right boundaries, you have to pass the parameter as boundary values using lr_eval_string function only.. In the below screenshot you can see that P_Server is the correlation parameter and it has been as the Left Boundary using lr_eval_string function.