BAPI or FM to update status to each line item in transaction PR05 (Travel Expense Manager)

Hi Team,

               I would like to know whether there are any BAPI or FM to change the status , values of the line items for the transaction PR05 (Travel Expense Manager) . I have a requirement where i have to change the status of each line item (example approve or reject ). I am not able to find a BAPI/FM for changing the line item values and status of the individual item.

Also, can you also help in finding the FM to update the comments section for the transaction PR05.

Thanks in advance