In recent years, Sam’s Club CEO Rosalind Brewer has led the warehouse store’s efforts to compete for Costco’s more affluent shoppers, but as sales at the Walmart-owned chain remain unremarkable, Brewer will soon retire.

Sam’s Club announced Brewer’s impending departure in an SEC filing [PDF] Friday, noting that she would retire from the company effective Feb. 1 after spending five years at the helm of the retailer.

Brewer will be replaced by current Sam’s Club chief merchant John Furner.

Under Brewer’s lead, Sam’s Club has implemented several initiatives intended to undercut its rival Costco.

For example, last summer, the company took advantage of Costco’s switch from an American Express-branded store card to Visa by parodying the other company’s signage and offering Costco card holders the opportunity to enter the store and browse.

For its part, Sam’s Club began accepting both Visa and American Express cards in early 2016.

(Related — Costco Vs. Sam’s Club: Which Warehouse Club Should You Choose?)

In Feb. 2016, Sam’s Club made plans to overhaul its biggest-selling category — groceries — by focusing on just one house brand, Member’s Mark, as well as adding more organic and specialty fine foods to its aisles.

At the time, Brewer told Fortune that the changes were a “reset for our business,” noting that the company knows that in order to compete with Costco and other retailers it must “win in food.”

Still, Fortune reports that despite the initiatives Sam’s Club continues to struggle to close the gap, as its recent 1.4% growth wasn’t enough to meet Costco’s sales.

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