For months, The Press Hotel and two of Maine’s best-known chefs have been trumpeting their partnership in a new venture – M.C. Union, the restaurant in the boutique hotel on Congress Street in Portland that’s expected to open in May.

Suddenly, in what a spokeswoman said was a mutual decision between the chefs and the hotel, that union is dissolving.

James Beard award-winning chefs Mark Gaier and Clark Frasier have taken their initials off the restaurant and will not be involved in running it. The highly anticipated new dining spot will now be called simply Union Restaurant, and an executive chef picked by Gaier and Frasier will be in charge.

Carla Tracy, a public relations consultant for the hotel, said the change in the relationship was “an amicable decision” officially reached Wednesday.

Frasier confirmed the shift in the partnership Thursday, but would not elaborate, adding that he would have more to say next week.

“There’s a little bit of a change and we’re still kind of talking about that, so I really can’t comment at this time,” he said.

He did say he thinks the change “will be good” and “things are working out very nicely.”

Frasier and Gaier have owned several Maine restaurants together, including the celebrated Arrows in Ogunquit, which they closed last year after 25 years. Their two branded restaurants, M.C. Perkins Cove in Ogunquit and M.C. Spiedo in Boston, have both incorporated the chefs’ initials into their names, and M.C. Union was expected to be the third.

The hotel and restaurant were supposed to open May 6, but that date may be pushed back to May 11, Tracy said. Officials from The Autograph Collection, a group of boutique hotels that includes The Press Hotel, will make that decision on Monday, she said.

Tracy said Frasier and Gaier helped develop Union’s concept and helped the new executive chef, Joshua Berry, connect with local farmers and other purveyors who will be supplying kitchen with their products. They also had “a heavy hand in the design and the look of the restaurant.”

“Mark and Clark have said (the restaurant) will have their fingerprints all over it,” she said.

Berry is a Maine native who most recently worked at the Stowe Mountain Lodge in Vermont. Previously, he was executive chef at The Balsams Grand Resort in New Hampshire.

Berry said that coming to work in Portland is “a dream.”

“I grew up in the Casco-Naples-Bridgton area, and Portland was my big city,” he said.

Berry described how thrilled he was to meet – and cook for – Frasier and Gaier when he tried out for the position. The three chefs developed Union’s menus together.

Berry said the restaurant will be “modern, but still really Maine,” with lots of marble, wood and black walnut ceiling tiles in the kitchen.

“They have designed a restaurant that is nothing like anything you’ve seen in Portland,” he said. “It’s definitely not the brick wall and wooden floor stuff.”

He said the food that will be served can be characterized as enhanced local cuisine that uses creative ingredients and “some cool cooking methods and preparations.” If he serves venison in the fall, for example, it might be enhanced with a Moroccan spice blend.

Berry said Union will be “a neighborhood restaurant.”

“It’s not precocious,” he said. “It’s not stuffy. It’s one of those places you want to be seen at, but anybody can come.”