According to the Professional in Business Analysis (PMI-PBA)Guide, a change request is a formal proposal to modify any document, deliverable, or baseline. A change request should include a clear description of the change, the rationale for the change, the impact of the change on the project, and the alternatives considered. A change request should also be evaluated for its feasibility, benefits, risks, and alignment with the project objectives and scope. In this scenario, the project manager should have assessed the change's overall impact to the project before submitting it to the CCB. This would have helped the project manager to determine if the change was necessary, beneficial, and feasible, and to communicate the pros and cons of the change to the SME and the CCB. This would have also helped the project manager to avoid or mitigate any potential conflicts or resistance from the SME or the CCB. Requesting that the sponsor approved the change request first, ensuring that the change request was aligned with the project scope, or submitting the change request directly to the CCB are actions that should be taken after the change's impact assessment, not before. These actions do not address the root cause of the situation, which is the lack of a proper impact analysis of the change request. References: (Professional in Business Analysis Reference Materials source and documents)
* Professional in Business Analysis (PMI-PBA)Guide, Chapter 6, Section 6.4.1.1
* A Guide to the Project Management Body of Knowledge (PMBOKGuide) - Seventh Edition, Chapter
8, Section 8.2.2.1

Explanation
This answer is based on the common ground principle, which states that effective communication requires that the parties involved share a mutual understanding of the meaning and intent of the information exchanged. To achieve common ground, the project lead should invite the participants to the workshop with sufficient lead time to prepare, so that they can review the scope statement, the project charter, and any other relevant documents. This will also allow them to raise any questions, concerns, or clarifications before the workshop.
By doing so, the project lead can ensure that the workshop is productive, collaborative, and focused on achieving a common understanding of the scope among the distributed project team. References: (Project Management Professional (PMP) Reference Materials source and documents) A Guide to the Project Management Body of Knowledge (PMBOK Guide) - Seventh Edition, Chapter
3: The Project Environment, Section 3.2: Project Stakeholders and Governance, page 57.
The Standard for Project Management, Part 2: Value Delivery System, Section 2.2: Project Planning, page 45.

Section: Initiation

Section: Planning