Royal Mail has confirmed that chief executive Moya Greene will step down after more than eight years at the helm.
Ms Greene will be replaced by Rico Back - the chief executive of the group's European subsidiary General Logistics Systems - who will take the reins at the start of June after the company releases its 2017-2018 earnings results.
The outgoing boss will formally step down from the board on July 19 following Royal Mail's annual general meeting (AGM) but stay on at the company until September in order to ensure an "orderly handover" to her successor.
Mr Back has been a senior Royal Mail Group executive and boss of GLS for 18 years, having been a founding member of German Parcel, which Royal Mail snapped up in 1999 and later rebranded as GLS.
He will stand for formal election to the role at the company's AGM in July.
Royal Mail shares were up nearly 0.4% in morning trading following the news.
The company said Ms Greene will use her retirement to "pursue a range of other interests, including developing her portfolio career".
The long-standing boss is currently a non-executive at easyJet and a trustee of Tate, and will become a non-executive director of Rio Tinto in the second half of 2018.
Royal Mail chairman Peter Long said: "When Moya joined in the summer of 2010, the company was balance sheet insolvent.
"Since then, Royal Mail has been transformed, including our privatisation in 2013 and two significant, ground-breaking agreements with the CWU.
"Alongside the strong financial position Moya has secured for the company, we have invested over £1.5 billion in our UK operation in recent years. We are one of the most favourably viewed brands in the UK.
"I would like to extend to Moya our sincere thanks for her tremendous contribution during a defining time for us."
The company also announced on Friday that it had appointed Sue Whalley as chief executive of Post and Parcels at Royal Mail UK, which accounts for all of the group's UK revenue and operations excluding Parcelforce Worldwide and Royal Mail International.
Ms Walley - a former chief operations officer and managing director of Royal Mail Letters and Network - will join the board on June 1.