Postal services across Lancashire were expected to return to normal after four days of walkouts by mail workers.
More than 150 postal returned to work at a Preston mail depot yesterday after strike action.
The workers at the Preston central delivery office walked out on Friday in a row with management.
The dispute centred around the refusal of bosses to suspend a manager involved in a row with a worker.
Yesterday (Tuesday) after a series of meetings members of the Communication Workers Union (CWU) decided to go back to work.
Lenny Crook, chairman of the North Lancashire and Cumbria branch of the CWU, said management were not going to budge on the issue while workers were on strike and there was a concern union members were affecting themselves and the service to the public by continuing with the action.
But he added senior managers who addressed the striking workers have given an undertaking to work with the union to resolve issues and concerns at the office.
He said: “The members have decided to return to work. Basically nothing has changed as far as the management position is concerned.
“The union put it to (members) that they have made a statement with the actions they have taken so far. This could go on forever and a day if they continue with the current position.
“They (the members) put it to the vote and decided to go back to work.
“The senior managers came out and addressed the members themselves after the vote and they fielded questions from them.
“They asked members to tell them what grievances and complaints they had and they did in no uncertain terms.
“The management, for their part, have given a commitment to work closely with the union on these issues around the office and to start that work straight away.”
No one from the Royal Mail was available to comment.
Managers and extra staff had been drafted in to handle the thousands of pieces of mail building up at the centre which covers PR1, PR2, PR3,PR4 and PR11 postcode areas.