NEC ECC: When a Project Manager rejects a programme which clause do they use to notify the Contractor? 13.4 or 13.7?

Simsai, the rule in clause 13.7 applies to any clause that requires someone to notify; the rule in clause 13.4 applies to any clause that requires reasons to be communicated. So the notification from the PM that the programme is not accepted should be communicated separate from other communications (13.7) and should cite one or more of the reasons given in clause 31.3 but in sufficient detail that the Contractor can comprehend the reasoning and address it in its resubmission (13.4).