Beth Corning, artistic director of Dance Alloy, compares "At Once There Was a House" to a Mahler symphony -- works that artists and audiences can grow into over time. "Dance Alloy Theater" Where: The Alloy will present Beth Corning's "At Once There Was a House" and David Shimotakahara's "Open Seating" at the Kelly Strayhorn Theater. When: Friday and Saturday at 8 p.m., Sunday at 2 p.m. and Monday at 7 p.m. Tickets: $13 -- 20 plus $50 Opening Night Special with dinner at the Red Room Cafe and $50 for a seat In the Wings; 412-363-4321 or www.dancealloy.org.

Dance Alloy Theater artistic director Beth Corning seemed to proclaim "At Once There Was a House" both literally and choreographically when she took over the company in 2003. Just as she methodically cleaned the Alloy's Neighborhood Dance Center, Corning is now working to turn her "House" work into a home for the company's upcoming performances this weekend at the Kelly Strayhorn Theater.

Sometimes it's not easy to determine when a dance has evolved into a substantial piece of choreography that will withstand the test of time. Of course, it has to have a firm sense of structure resting on an unwavering firm technical foundation.

But then the choreographer can rethink and reshape the configuration of the steps -- an ongoing restoration of sorts. George Balanchine was famous for altering solo parts to suit his dancers at the New York City Ballet. And alterations can creep into any dance over the years with new casts or new companies.

Dance Alloy artistic director Beth Corning always wrestles with those ideas in pieces like her "House." How to tell when a work is complete. How to tap the promise of change.

First she states that "the object of a repertory company is the fact that it has a repertory. Like going to the symphony, you go to hear a favorite, a Mahler symphony," Corning asserts. "And what that does, I feel, is that it not only profits the artists because they grow into works, but it also gives the opportunity to the audiences in that they start to own something."

When Corning first set "At Once There Was a House" on the Alloy, it was a group that she didn't know.

"It was one of the works I really liked," notes Corning. "And I feel that now I have a group of dancers that would be really interesting in it." Alloy dancers Michael Walsh and Maribeth Maxa were part of the original cast here. Since then Corning has added Stephanie Dumaine, Adrienne Misko and, new this year, Scott Lowe.

So she set about changing the piece, some sections "drastically," including two substantially reworked duets. In addition, the characters in the piece have a deeper development.

In some ways this "House" will have familiar surroundings, including the solos and some prop pieces. Yet Corning harkens back to the symphony, saying, "It might have the same notes, but different musicians might bring a new interpretation. And you come back to it four years older, four years richer with life experiences."

Corning uses Jose Limon's "The Moor's Pavanne," which the Alloy performed last year, as an example. "It has been amalgamated a hundred times over," she explains. "It has moved from the modern-based body to the ballet body. Now it's completely different because people's techniques have changed."

"But Jose kept changing it from the start as new people kept coming to do it," Corning adds. "I think a good work remains a good work and it can get better."