TULSA, Oklahoma - Big changes are underway at the COX Business Center in Tulsa.

A multi-million-dollar renovation project is more than halfway finished, but there is still a lot of construction equipment at the center and a lot of work ahead. Some major updates are happening inside and outside the center. The decades-old building in downtown Tulsa is getting a face-lift, with a new glass entrance architects said people will notice right away.

"We tried to add to it and not distract from it, and still allow the original design to read through, but give them a really great entrance,” Matrix Architects President Cecil Ricks said.

Once inside, visitors will walk through a newly-renovated "grand hall," leading them to an updated ballroom with higher ceilings. The room can be split into three separate spaces for different events.

"Clients will be able to come in here and pretty much rig anywhere in the ceiling. It's very open,” Ricks said.

Part of the lower level has been gutted, in preparation to become a new, upgraded kitchen.

Crews have been at work since last summer.

"Everything is on track,” Tulsa Vision Builders Senior Project Manager Andrew Witte said.

Tulsa Vision Builders is a joint venture of Flintco and Manhattan Construction.

Witte said the $52-million-dollar project is past the halfway point. Working on the center, which was built in the 60s', came with a challenge. Building codes were different back then and changes had to be made.

“Until you cut things open, you don't know what you're really dealing with. So that was a process in and of itself,” Witte said.

Both Witte and Ricks said working through that challenge will be well worth it.

"It's gonna be a nice addition to Tulsa and it's gonna … put us in a league with some larger cities who bring in larger venues and larger conventions and things we weren't getting before,” Ricks said.

Conferences and events are still being held here during the renovation. The project is expected to wrap up next summer.