@vijayvelchamy.v
Thank you for the confirmation. In such case we unfortunately don’t have any API that would let you do this easily.
It seems that the only option here would be to use setDataAtCell method https://handsontable.com/docs/javascript-data-grid/api/core/#setdataatcell to alter the values you need, export the file and then again using setDataAtCell reset the values to their initial state.
The whole logic could be done as a batch operation for the best performance and results. You can read more about it here: https://handsontable.com/docs/javascript-data-grid/batch-operations/
The cons of this solution is that if you allow users to do undo/redo operations, then the changes needed for export purposes would be in their changes stack.