Construction Project - Convert from Overhead to Buried

My property has telephone poles in the rear, carrying electric (ComEd), Comcast cable TV/internet service, and copper and fiber AT&T service.

As part of an upcoming construction project, I plan to have these telephone poles removed and the overhead Comcast service buried for me and the neighboring property to the east.

We finished our architectural drawings and applied for a building permit. However, the city requires me to obtain a letter from ComEd, Comcast, and AT&T indicating that they have reviewed the architectural plans and are OK with the proposed plan to bury the service.

I called the Comcast Business customer support number (800-391-3000) and, after being on and off hold a few times, was told I needed to go into an Xfinity store to request an engineering review of my property.

I'm not confident that the customer service representative I spoke with understood the situation or was directing me correctly—I can certainly go to an Xfinity store, but that doesn't seem correct to me. 

Does anyone know how I can start this process with Comcast and, most immediately, get a letter indicating that we are OK with proceeding with the construction plans?

To clarify, I am a current Comcast Business customer.