Report output - changeable

Hello

maybe a silly question, but then it will probably be easy to answer.

Normally reports like Invoice , Purchase order etc are developed using xml publisher etc

but from what I remember they collect the data, and the data cannot be changed. (as in pdf format)

(unless you change something on the original data ofcourse and run the report again)

-- is there a way of changing the data in the report itself

--if i would not develop it for pdf, but for excel would that do the trick

or any other option?

Thanks,

els