Hello 
,
It is difficult to say how exactly it looks in your scenario but it seems you could use the combination of “XML - Parse XML” and “XML - Create XML” modules.
The “Create XML” module allows the creation of XML files in the specified data structure (it can even be generated based on the sample file).
You could then parse the incoming data and use them in the “Create XML” module in addition to data from other modules.
That would effectively work as replacing the data in the existing file.
I hope it makes sense.
Cheerio 