If anyone try to book an intercompany transaction and want to change Debit and Credit amounts in distribution window these fields are disabled.
So to change the distribution amounts you have to change Originating Debit and Originating Credit Amount as shown below.
Since Co. ID is enabled in distributions window this is intercompany transaction, so the debit and credit amounts are disabled. You have to modify Originating Debit and Originating Credit amounts.
If you are booking non-intercompany transaction then Originating Debit and Originating Credit amounts will be disabled in Distribution window then you have to modify Debit and Credit Amounts.