Once a protocol Amendment has been reviewed and approved, a formal written notice of approval will be sent to the Principal Investigator.
As with other reviews, approval for modifications to a protocol are managed by Board Action Notices signed by the IRB Chair, specifying the current terms and conditions for any changes to the protocol or documents associated with the research protocol. These notices are sent for all categories of projects (Exempt, Expedited and Full Board), and are usually dispatched within 48 hrs of approval (whether approved by the IRB Chair alone, or by a convened Board).
Recall that a modification to a protocol cannot be implemented until after IRB approval. Thus, investigators should build in sufficient time for review and approval before a change needs to be implemented.