Diagnosis
The date relationships are only defined for information purposes.
The system does not check the due date of receivables paid via this
business partner.

Procedure
You can only change the payer of a condition item by maintaining theconditions detail screen. This is then valid for all planned recordsresulting from this condition which have not yet been posted.
If debit positions which have already been posted are paid by a newpayer, you have to reverse the debit position and then change the payerin the condition.