Once a conflict message has been identified, an application or form can resolve the conflict as follows:
It locates the attachments in conflict by reading the PR_IN_CONFLICT property on the attachment table.
It resolves the conflict between these attachments in one of two ways:
It can select the winning message based on almost any criteria.
It can merge the contents of the messages in conflict.
Using the MAPI IMAPIProp::CopyTo method, it copies the resolved properties to the main message (the message to which conflicting messages are attached). Then, the attachments are deleted.
When all conflicting message attachments are deleted and changes are saved, Microsoft Exchange Server automatically clears the message's MSGSTATUS_IN_CONFLICT bit. You do not need to programmatically reset this bit after the conflicting message attachment is deleted.