Top row: TRACE whitelight image. Purple contours show areas with changes in the magnetic field azimuth larger than 5° and yellow contours are areas in which the longitudinal magnetic field switches from a positive sign to a negative sign or the other way around. All values are retrieved through the inversion and are selected at optical depth log(τ_500   nm) = -1. The second and third panels show the change in B_trans and B_long. White areas are regions of increase in B_trans/B_long and areas of decrease are black. R1 (red contour), R2 (purple contour), and R3 (yellow contour) in the last panel are locations of simultaneous change in B_trans and B_long greater than 400 G in both parameters. Last three rows: average inclination angle γ and the average B_trans in the regions R1, R2, and R3. As in Fig. 4, the inclination angle runs from 0° to 180° with γ = 90 °, representing a transversal magnetic field and an angle of γ > 90 °, constituting a negative longitudinal magnetic field (vector pointing toward the Sun). The error bars are the standard deviation in γ and B_trans over a region in the umbra outside the flare site. The soft X-ray GOES curve is overlaid in blue.