128It is also clear from the case-law that the principle of the protection of legitimate expectations may be relied on by any economic operator on whose part national authorities have created reasonable expectations. However, economic operators cannot justifiably claim a legitimate expectation that an existing situation which may be altered by the national authorities in the exercise of their discretionary power will be maintained (see, to that effect, judgments of 10 September 2009, Plantanol, C‑201/08, EU:C:2009:539, paragraph 53, and of 11 July 2019, Agrenergy and Fusignano Due, C‑180/18, C‑286/18 and C‑287/18, EU:C:2019:605, paragraph 31).