Need Help on modifying infocube data using ABAP program

Hi All,

I have a info cube in APO-BW, it has characteristic, Nav Attrib and some key figures which holds below example data:

Characteristic -

Nav.Attrib -

Keyfig

XXXX -

NNN----

KKK

Now the requirement is to develop a ABAP program where user enters the Char value on selection screen for e.g. user enters Char Val as 'XXXXX' on sel screen, program should display the second screen as follows:

Characteristic -

Nav.Attrib

XXXX -

NNN

Here on the second screen user should be able to change the NavAttrib Value and the program should modify the entry in Infocube/InfoObject according to the changes made to the Navigational Attribute.

Are there any BAPIs or Function Modules available for modifying the infocube/infoobject data, I know one function module which inserts data to infocube i.e RSDRI_CUBE_WRITE_PACKAGE but i am not sure whether it modifies the existing data.

Could some one please help me out.

Thanks in Advance,

John