Thousands of teachers who worked at 24 struggling schools the city wants to revamp are now getting instructions from their union and the city about how to proceed, even as the dispute over the schools’ futures continues in court.

The Education Department sent out two letters on Wednesday. One was sent to 150 teachers who are known to have applied to transfer to another school, according to education officials. It asks them to inform the city whether they still intend to transfer by completing an online survey, due July 27. Decisions to transfer are binding.

An Education Department spokeswoman, Erin Hughes, said the city sent a second letter to 2,700 teachers who were assigned to the 24 schools in 2011-12, saying they did not have to take any action to reclaim their jobs. It asks them to state whether they have changed their plans, though whatever they say is not binding.

They can seek other jobs in the city schools through Aug. 7, Ms. Hughes said.

The teachers are allowed to return following last month’s ruling by an arbitrator, Scott Buchheit, who found that the Education Department violated union contracts for teachers and supervisors by letting go all staff members at the 24 schools and making them reapply for their positions. The city then lost an effort this month to obtain a temporary restraining order preventing the arbitrator’s decision from taking effect.

The parties are due back in court on July 24, before Supreme Court Justice Judge Joan B. Lobis.

The 24 struggling schools were given new names, and most were assigned new principals in an aggressive effort to shake up their culture and bureaucracies. The unions pushed back, and now the two sides seek resolution from the court.

Meanwhile, staffs at the affected schools are scrambling to get ready for a new school year just seven weeks away. The Education Department letters mark the first concrete communication to the teachers and other affected union members, like counselors and paraprofessionals, about their employment status.

“It is important to note that in many cases, 50 percent of teachers did not reapply for their jobs at the new schools,” Ms. Hughes said in an e-mail to reporters. “The N.Y.C. Department of Education received an unprecedented response for the 3,000 vacancies at these new schools. Over 26,000 applications were submitted by about 8,000 unique applicants.”

Martin Haber, who has spent the past 23 years at John Dewey High School, said he was not offered a teaching position at his school by the new administration. Mr. Haber, 54, said he didn’t get along well with the new principal and expected things to be awkward this fall.

“I’m going back to a school that I won’t even recognize,” he said, adding that teachers were told to remove many belongings and classroom exhibits. But he added, “I’m going to make sure that it’s not tense.”

The prospect of having to work with teachers they didn’t want in their buildings presents a challenge for supervisors, too.

“They fully expected to come in and revamp the schools,” said a source knowledgeable about the staffing at some schools, and spoke on the condition of anonymity. “Not only are these people back. They’re back with their tongues out.”

It’s not clear whether any of the new principals would have to leave the schools, should the unions prevail in their lawsuit.

It’s also unclear whether the schools will have as much financing as they were hoping to have in the fall. The city was counting on millions of dollars in federal school improvement grants, which were held up in January by the state when the city and the United Federation of Teachers weren’t able to agree on a new teacher evaluation system for these schools. Mayor Michael R. Bloomberg’s administration then changed course, deciding to close the schools and reopen them with new names and many new staff members in order to qualify for the funds through a different strategy called turnaround.

But now that an arbitrator has said that staffing changes violated union contracts, the entire turnaround plans are in limbo. Those involved with the schools worry about possible budget cuts. Many of the schools were paired with outside nonprofits that started working with them last September, and their contracts may have expired.

On Tuesday, Mr. Bloomberg said he still hoped the city would prevail in court next week. “At the moment we have to assume that they will come back,” he said, referring to the teachers. He said the 30,000 students enrolled in the schools couldn’t afford to wait for the changes he sought.

“As God is my witness, I will not walk away from those kids,” he said, adding that he didn’t know what the city would do if it lost its appeal. “But we’re not going to let bureaucracy get in the way of doing everything we can to help those kids.”

In an e-mail to the teachers on Tuesday, the United Federation of Teachers president, Michael Mulgrew, told them to hang tight and said the union would continue fighting the city’s “misrepresentation” of its contract.

“Despite all of the obstacles the Department of Education has thrown in your way this past year, you have stood strong for your students, your schools and your profession,” he wrote. “Our focus now turns to doing everything we can to make sure that your schools have a good opening in the fall.”