A CE can only exist if an event has actually (or is expected) to occur. In your case it looks like a CE has been notified, although it is unclear whether a valid instruction has been given to change the Works Information.
It may be that the notification form includes a box that has been 'ticked' to effectively instruct this change. There is no requirement to issue a formal 'Project Manager's Instruction' form to validate the instruction, although the communication requirements at clause 13 have been written with the intention that contract communications are clear and obvious, including the requirement for notifications to be communicated separately from other communications,
I would suggest confirming the status of the instruction with the PM to ensure that any consequent actions you take are compliant.
It may be that the notification form includes a box that has been 'ticked' to effectively instruct this change. There is no requirement to issue a formal 'Project Manager's Instruction' form to validate the instruction, although the communication requirements at clause 13 have been written with the intention that contract communications are clear and obvious, including the requirement for notifications to be communicated separately from other communications,
I would suggest confirming the status of the instruction with the PM to ensure that any consequent actions you take are compliant.