In case of an already authorized expense sheet where allowances are wrong (for example wrong amount defined in the abroad rule), the normal way a wrong expense sheet (duplicate it and set the duplicate to minus) does not work since in the Cloud version Gross Amount in Payment Currency is always recalculated after saving the line into positive value. 

For example : 

In this case faulty expense sheet was duplicated and quantity of allowance was set to -1 and before saving the line Gross Amount in Payment Currency is correctly negative.

After saving the lines all values are negative but Gross Amount in Payment Currency is positive.

Is there any solution known in standard functionality to correct allowance of already authorized expense sheets?