Update field

Hi

I want to update the mara- labor field thru BAPI.

BAPI_Material_savedata will work??

if the field value is F,Iwant to update it as FG thru bapi

can you please tell me which BAPI i have to use and parameters....any example plz?

How can i update documents also thru bapi?BAPI_DOCUMENT_CHANGE is the fm i found,plz explain on this.

Thanks in advance