The 19-year-old Brazilian defender has made only four appearances for Pep Guardiola's team since arriving in January.
According to sources, Reis is unhappy with the limited playing time and wants to join another club on loan this summer.
His goal is to gain more consistent experience and increase his chances of being selected for Brazil's 2026 World Cup squad.
FC Porto and Bayer Leverkusen have been mentioned as potential destinations for Reis, with both clubs reportedly making loan proposals.
