Hello, 

If you're familiar with the technical aspects of Odoo, you can modify the XLSX report by following these steps:

1. Navigate to the account_reports module.
2. Locate the file account_report.py within this module.
3. Find the method named get_xlsx in this file.
4. Modify the get_xlsx method to achieve your desired changes in the XLSX report.

Please note that modifying core functionality can have unforeseen consequences. Make sure to test your changes thoroughly in a development environment before applying them to a production system.

If you're not familiar with Odoo's technical aspects, I strongly recommend seeking assistance from an experienced Odoo developer. They can help you make the necessary modifications safely and effectively.