Answered: NEC ECC: Omitting of works

From what you say - i.e. "The drawings are annexed to the Employers Work Specification which forms part of the Works Information." - these are part of the Works Information and therefore part of the original contract, even though the accompanying detail might not be there in the Employer's Works Specification as per the other drawings.

Therefore, the Project Manager, if this is no longer wanted can omit them from the Works Information by giving an instruction changing the Works Information, which would be a compensation event and one of only two for which the Prices can be reduced.