PO Form Title for creation/change

Hello,

Our client is looking for different titles on the PO form such as:

Purchase order ##### - initial creation of PO

Purchase order ##### changed - when any change happens on the PO

Purchase order ##### cancelled - when all the items are deleted on the PO

We noticed that the standard form has 2 headers: Purchase order ##### and Changed Purchase order #####, which is determined by a script in the backend, specifically based on the below flag.

Form.frmHiddenGlobalFields.frmHiddenTitle.txtChangedFlag

Questions:

1. When/How does this flag get set? Eg: When I changed PO header/item quantities, the header still did not change to 'Changed Purchase order #####'. Are there any config settings governing the value of this field?

2. How can we set the value of this flag for the cancellation scenario? Is there a BADI available for developers to manipulate this?