Provided the communication complies with the requirements of clause 13, then it would be a valid instruction. There have been other posts on this subject recently which you can find in a search.
If the instruction changes the Works Information then the Project Manager is also obliged to notify the matter as a compensation event, or, if the PM fails to do so, the Contractor should notify accordingly.
If the instruction changes the Works Information then the Project Manager is also obliged to notify the matter as a compensation event, or, if the PM fails to do so, the Contractor should notify accordingly.