This post gives a recommended procedure for making changes to inventor or applicant details of a PCT application.
TL;DR - do this centrally at WIPO under Rule 92.bis.
It is a very good idea for any changes to the applicants or inventors of an International patent application to be made centrally at WIPO under Rule 92.bis, before the various national phases of the PCT application are entered.
If the change is not recorded centrally, it can potentially be very troublesome and time consuming (not to mention expensive) to have to record the change before each national patent office.
For example, in Singapore, if a change had not been made centrally, we would have to file a separate request to change those details during the Singapore national phase of the PCT application. Where the correction is of an error in the indication of the applicants or inventors, we will at the very least be required to set out in detail how the error occurred. There is a possibility that IPOS may ask us to provide further detailed evidence of the error.
On the other hand, if we can show that a request has been made centrally at WIPO, the process is much easier - we just have to write to them to point this out and enclose a copy of the PCT/IB/306. Usually, no other documentary evidence is needed and the change is simply recorded.
In order for a request to WIPO under Rule 92.bis to be effective, WIPO has to receive the request by the 30 month deadline. The change doesn’t necessarily have to have taken place by then, but the letter must reach the International Bureau of WIPO by that date.