John Lewis is looking to slash the size of its flagship store on Oxford Street in London, as part of efforts to turn around the business.
The department store branch, which has had a presence in the capital since 1864, could cut its trading space by almost a half.
Its sister business Waitrose, meanwhile, is shutting a further three branches and selling one to Tesco, putting 124 jobs at risk.
John Lewis has asked Westminster council to approve plans to convert excess space into offices to rent out, the Evening Standard first reported.
A spokesperson said that obtaining the permission, for floors three to eight, would give it more flexibility on how they use the space more efficiently.
The move comes after the firm said it could turn some department stores into affordable housing as more shoppers desert bricks-and-mortar in favour of online shopping.
John Lewis insisted that no decisions have been made to go ahead with an overhaul of the store on Oxford Street.
Separately, Waitrose said it is closing three shops in Caldicot, Ipswich Corn Exchange and Shrewsbury. It is also selling its supermarket in Wolverhampton to Tesco, and safeguarding 140 jobs.
There will be no further supermarket closures this financial year to January, taking the total to seven. Last year it shut 12 Waitrose stores as part of an ongoing review of its properties launched three years ago.
Dame Sharon White formally joined in March from media regulator Ofcom and is on a mission to turn the mutual’s fortunes around.
She will lay bare the damage coronavirus has been wreaking on the mutual finances in its interim results on Thursday.
John Lewis has been battered by the pandemic after it was forced to shut stores for almost three months. The loss-making department store chain has been leaning on profitable Waitrose to survive.
The three shops earmarked for closures will stop trading on Dec 6, with the shop in Wolverhampton staying open until the end of the year.
Staff will now enter a consultation about redundancies, but the firm is hopeful that it will manage to transfer some roles to other Waitrose or John Lewis sites nearby. It is also offering them additional support to find other roles.
Bérangère Michel, an executive director, said closing any shops was always a last resort.
The news comes after it announced it would shut eight of its 50 John Lewis branches, putting 1,300 jobs at risk. It has a workforce of more than 80,000.
Despite the cuts on the frontline, Dame Sharon has been hiring executives after an exodus of senior staff under her predecessor Sir Charlie Mayfield.