How to prevent the employee's expense account from being automatically assigned in a PR?

Hi colleagues, I am facing a problem, we are implementing the Employee Expenses and Self-Service Procurement module.

We are adding to the employees a default expense account.

And when the employee goes and enters a purchase request, the application sends by default as a charge account, the expense account that the employee has in his/her profile.

The charge account for the requisitions should not be the same expense account that the employee has, is there any way to avoid this?
Avoid that the charge account for purchase requisitions is not the account that the employee has, but the account that I have configured in the purchase mapping set.