To retrieve approver's personnel id for workflow item container

Hi all,

I have a requirement to change approver's name format for historical data of workflow item container.

As-is: Nick name + Last name (example: Chris Sam)

To-be: Title + First name + Last name (example: Mr. Christoper Sam)

I'm using the function SWW_WI_CONTAINER_READ to retrieve container data details but it returns approver's name, not personnel id.

Can anyone tell me how to access approver's id for workflow item container?

I really appreciate any input/hits/clues in advance.

David Park