Portion of the spectrum of HD 117290 observed at 4 epochs. The wavelengths are in the laboratory reference frame. The same lines as in Figs. A.1 to A.3 are identified even though some may not be seen in the present spectra. The narrowing splitting of the Fe II λ 6149.2 Å line clearly shows the decrease of the mean magnetic field modulus with time. The increase in intensity of the Cr lines from the first observation to the most recent one is particularly notable from comparison of the Cr II λ 6147.2 Å line with the neighbouring Fe II λ 6147.7 Å and λ 6149.2 Å lines. Other Cr lines show similar variations. The strengthening of the Nd III λ 6145.1 Å and Pr III λ 6160.2 Å with weakening ⟨B⟩ is also visible. Comparison of the top two spectra, obtained respectively with FEROS and UVES at epochs between which the star did not significantly vary, allows one to assess the effect of the resolution on the line profile appearance.