The owner's request to change the business center to a restaurant constitutes a material change in the project's scope. According to standard owner-architect agreements, such a change necessitates an adjustment to the architect's schedule and compensation. To maintain the original construction start date despite the consultant's required four-week extension, the architect would likely need to authorize the consultant to accelerate their work (e.g., through overtime or adding staff). This acceleration is an additional service that requires additional compensation. Therefore, the architect's first action must be to inform the owner of the cost implications of their request and seek authorization for the adjusted compensation needed to fund the schedule acceleration.

B. Approve the design loads of the new mechanical system following the next quality control review.

This is a technical design review step that occurs after the new design work is performed. It does not address the immediate project management issue of schedule and scope change.

C. Receive the owner's approval of the schedule change in writing from the consultant.

The consultant reports to the architect, not the owner. The architect is responsible for obtaining approvals from the owner. This option incorrectly describes the contractual lines of communication.

D. Change the C401 agreement to reflect the additional four-week extension.

Modifying the C401 agreement is a necessary administrative step, but it can only happen after the architect has discussed the options with the owner and received a decision on how to proceed (i.e., extend the schedule or pay for acceleration).

1. AIA Document B101™–2017, Standard Form of Agreement Between Owner and Architect.

§ 4.1 & § 4.2.1: These sections stipulate that a material change in the project initiated by the owner is considered an Additional Service. The architect must notify the owner promptly and obtain written authorization, which includes adjustments to compensation and schedule, before proceeding with the additional work. This supports approaching the owner first regarding compensation.

2. AIA Document C401™–2017, Standard Form of Agreement Between Architect and Consultant.

§ 4.3: This section outlines that if the consultant's services are changed due to revisions required by the owner, the consultant is entitled to an equitable adjustment in compensation and schedule. This confirms the mechanical engineer's request is valid, and the architect must now manage this change with the owner.

3. The American Institute of Architects, The Architect's Handbook of Professional Practice, 15th Edition.

Chapter 9.3, "Managing Project Scope": This chapter emphasizes that when a client requests a change, the project manager's primary responsibility is to evaluate and communicate the resulting impacts on scope, schedule, and budget to the client for a decision before proceeding. This aligns with option A as the first critical step.