(Adds details through on history of new GPA, Via Varejo appointees)

By Gram Slattery and Tatiana Bautzer

SAO PAULO, Feb 19 (Reuters) - GPA SA, one of Brazil's largest food retailers, announced on Monday evening a shake-up of its management team, replacing its CEO and the head of a subsidiary just moments before releasing full-year results.

In a statement, GPA announced Peter Paul Estermann as its new chief executive officer effective in April, replacing Ronaldo Iabrudi who had served in the post since 2014 and will now become vice chairman of the company's board.

In a related move, Flavio Dias will become the CEO of appliance and electronics subsidiary Via Varejo SA, replacing Estermann, who had been serving in that post.

Under Estermann's leadership, Via Varejo has adapted a tech-savvy, infrastructure-light retail model that has significantly boosted margins and profits.

GPA, itself controlled by France's Casino Guichard Perrachon SA, had put Via Varejo up for sale in 2016, but the company attracted little interest as the company's then-traditional, infrastructure-heavy formats dragged on profits and kept costs stubbornly high.

Estermann's team is credited with a turnaround by betting on smaller formats and focusing on e-commerce initiatives, among several other strategies.

Via Varejo earlier on Monday posted a 129 million-real ($39.9 million) profit, reversing a loss of 251 million reais in the same period last year and pushing up shares over 2 percent.

GPA, buoyed by a consumer-led rebound in Brazil and a timely bet on wholesale formats during a recession, has also performed well, though perhaps not as impressively as its subsidiary.

The company posted fourth-quarter results on Monday evening that hit analysts' estimates, though some of the company's more traditional grocery formats continue to drag on margins.

"We're living in an era of transformations in retail, and I don't see a better person than Peter to guide GPA in this next cycle," GPA Chairman Jean-Charles Naouri wrote in the statement.

Flavio Dias, Via Varejo's new chairman, led the company's online division and was described in a separate statement released by Via Varejo as an e-commerce pioneer in Brazil.

"His selection reinforces our commitment to keep investing in the integration of physical retail and e-commerce," Vice Chairman Arnaud Strasser said.

According to the companies, the change of command at Via Varejo will become effective on April 26, while the changes at GPA will become effective the following day.

($1 = 3.24 reais) (Reporting by Gram Slattery and Tatiana Bautzer; Editing by Grant McCool and Lisa Shumaker)