Roughly 10,000 flight attendants walked off the job after midnight on Saturday, prompting cancellations that have impacted around half a million people.

The union had defied an order from a regulatory tribunal to return to work on Sunday, forcing Air Canada to roll back plans to partially restore service.

But after resuming talks late on Monday, the union said it had reached a potential deal with the airline that it would put to its members for consideration.

“The Strike has ended. We have a tentative agreement we will bring forward to you,” the Canadian Union of Public Employees’ (CUPE) Air Canada branch said on Facebook on Tuesday.

“We are required to advise our membership that we must fully cooperate with resumption of operations,” the statement said.

Air Canada said in a statement that it would “gradually restart its operations” after reaching a “mediated agreement” with CUPE.

It said the first flights were scheduled for Tuesday evening but warned that full service may not return for seven to 10 days.

“Restarting a major carrier like Air Canada is a complex undertaking. Full restoration may require a week or more, so we ask for our customers’ patience and understanding over the coming days,” Air Canada president Michael Rousseau said.