How to update Execution periods in Appraisal Document

Hi Friends,

I am able to update validity period in apprailsal docuement using HRHAP_DOCUMENT_SAVE function module through S_HEADER_DATES parameter.

But i want to update Execution periods also.there is no specific parameter for this.

And also i am able to update Appraise and Appraiser.But how can i update Reviewer.

Can any please let me know ..

Sudheer.