The city and teachers union still have not reached an agreement on how to overhaul more than 30 struggling schools. But city school officials said that, deal or no deal, they will announce those plans at the end of this week.

Though the original due-date for submitting school improvement plans was today, state education officials granted the city’s request to postpone the deadline to Friday. That leaves the city and teachers union four days to reach an agreement on which of three federal improvement strategies each of the schools should undergo.

Of the 43 schools that are eligible for school improvement grants, but have yet to begin using them, 31 are waiting to be told if they’ll be transformation, turnaround, or restart schools. Under each of these three plans being considered, schools would receive hundreds of thousands of dollars in federal grant money.

A spokesman for the city’s Department of Education, Jack Zarin-Rosenfeld, said that the city had asked for an extension in part to have more time to negotiate with the union.

Last week, union officials said they were hopeful a deal would be reached by today, but that has not happened.

“We will continue to have conversations with the DOE until we reach a solution that is best for the school system,” said a spokesman for the union.

If the city and union can’t agree on a plan for each school, city officials said they would proceed with the “restart” model.

The restart plan involves closing a school and reopening it under new management — either as a charter school or as a district school run by a school management organization (for example, New Visions). Because this plan does not require the city to fire teachers or principals, it can be used without the union’s cooperation.

The other models are known as transformation and turnaround.

The transformation model is less invasive. This plan relies on removing a school’s principal, bringing in extra support services, and experimenting with longer school days and new teacher training.

The “turnaround” model calls for a school’s principal to be replaced and its teachers and administrators to reapply for their jobs. Only 50 percent of the staff can be rehired, but the students remain the same.

The transformation model is already being used by 11 schools. Twelve schools will be phased out beginning next year under a fourth plan, called the closure model, and replaced with new schools using the federal grant money.