The delegation of PM duties under ECC needs to be notified by the Project Manager named in the CDP1. It’s unclear whether you are named PM in the CDP1, but if so it’s not an instruction as such that you need to issue (PMI), I would suggest you raise a general communication. It does need to be notified separately from other notifications (cl.13.7), so avoid including this in minutes. You may also wish to be set out which duties you are delegating (rather than all) and also consider whether you need to cancel any delegations.
The equivalent provisions within the PSC contract for changing the Employer’s Agent are set out in the secondary option X10 (cl. X10.2), but there are some differences between the ECC/PSC. The wording in the PSC is slightly less flexible that the wording within the ECC. The Employer may replace the Employer’s Agent (by writing a letter for example) in much the same way that the Employer may change the PM under the ECC. However the authority/duties of the EA, are defined at the start of the contract and set out in the contract data. You will therefore need to check whether you are changing both the EA and also the duties set out in the contract data. The entries in the contract data cannot be changed by one party (i.e. Employer), without mutual agreement. Technically the manner in which the agreement can be changed is typically set out in the form of agreement, so you would need to check this. Its highly likely for example that if the contract is signed as a deed it technically requires a deed to change the entries in the contract data, however from a practical perspective, recording the change and its agreement in writing between both parties, should be sufficient in most instances i.e. a short letter from the Employer which asks the Consultant to acknowledge and confirm their acceptance of the changes by signing and returning it.