The phrase "attendant office" is correct and usable in written English.
It can be used to refer to an office that provides support or services related to a specific function or event.
Example: "The attendant office will assist you with any inquiries regarding your application status."
Alternatives: "support office" or "service office".
When she returned to health, Marguerite McCausland worked in the flight attendant office for United for a couple more years, then returned to school and earned a degree in information systems.
In six days, Mrs. Clinton and 11 other freshmen senators will descend on the Capitol for a series of tutorials, photograph sessions, lunches and tours through the maze-like back rooms of the Senate and its attendant office buildings.
The state and its attendant offices have never been comfortable when large groups of mainly working-class men gather together in a common purpose.
Dishwashers, maids, landscapers, construction workers, short-order cooks, car-wash attendants, office cleaners, etc.
You leave the way you entered, and pick up your bag, wallet, phone and belongings from the attendants' office outside the entrance – nothing is allowed in, including cameras.
He was an attendant at the post office in Pio XII and had spent the weekend visiting a sister.
Over the years, she has worked as a home attendant and an office worker on Wall Street.
At 6 p.m., the box office attendant with the clipboard called out, "Jeremiah!" Mr. Kane walked in and soon ambled out with two tickets.
At 9.30am on my first day, an office attendant appeared to make me a cup of Karak, an excessively sugary local tea.
The attendant email, showcasing Office's summer collection of sandals, slip-ons and those weird, cloggy platform soles that seem somehow orthopaedic and slutty at the same time, advised readers: "Just don't forget to shave them".
After retiring in 1988, he served as a driver for Meals on Wheels for 10 years, an office attendant for the Hospice Family Care in Orange County for four years and a member of the Executive Board for the American Legion, Post 291 for six years.
