Append a cell / raw to saved/existing xls file


Hi Team /All.

I'm new to NPOI, I had started today and I must say well done !.
I have the following issue and I hope you can help / explain it to me.

I would like to write 10 different cells to a xls file, But i must save the file after each modification.
I tried to use the ".Write(file)" method and I get a big file but with results of only the first save. (all other 9 changes are not saved).

I tried to search for this issue but I could not find an answer.

Thanks in advance,