Take it to an instrument repair shop (band instrument). Find a good one in your area. What can be done is to resize both the long joint and the foot joint using a mandrell and through peening. Assuming you have a plated flute (silver or nickel over brass alloy) its touchy but not tremendously difficult. More care is needed on the solid silver flutes such as a Haynes or an upmarket Gemeinhardt, but still accomplished without too much difficulty.