SAO PAULO, April 28 (Reuters) - Brazilian retailer Casas Bahia is set to restructure 4.1 billion reais ($801.36 million) in debt, which would remove substantial pressure from its short-term cash flow, the company said on Sunday.

As part of a broader plan to turn around its business, the company filed a request for an out-of-court debt rescheduling of four bond issues and some debt with financial institutions, it said in a securities filing.

The move would improve the firm's cash flow by 4.3 billion reais in the next four years, as it would extend the average maturity of the obligations to 72 months from 22 months currently.

The plan was already agreed upon by lenders representing 55% of the debt in question, the firm said, which would secure its approval. It still needs to be approved by the firm's shareholders.

Casas Bahia, formerly known as Via, announced last year a series of restructuring measures that also included shrinking inventories, closing stores, and laying off thousands of workers.

Year-to-date shares in the retailer fell 52.2%.

($1 = 5.1163 reais) (Reporting by Peter Frontini; Editing by Michael Perry)