pre-event condition to more than $65(74)$ km s$^{-1}$ during the event for  1335(1336) [Å]{}. The difference of 8 km s$^{-1}$ in the width of two lines of could be attributed to the presence of several absorption features present within the wavelength span [@2015ApJ...809...82G]. The line width of two lines increased from $\approx35$ km s$^{-1}$ to about 60 km s$^{-1}$. A close examination of time of enhancement in intensities, Doppler shifts, and line widths reveal that the line widths started to increase about 2 to 3 minutes before the start of increase in the intensities. Moreover, the Doppler shifts started to increase about a minute later than the start of increases in the line widths.

During the event, the spectral lines of and appeared in the spectra, which were not present in the pre-event conditions. This provided us an opportunity to estimate electron densities during the event . For this purpose, we used the density sensitive line pair of O [iv]{} $\lambda$1399/$\lambda$1401. We obtained average line profile at A between the time interval of 13:03:41 UT to 13:04:40 UT to improve the signal. Figure \[fig:density\], shows the averaged line profiles (left panel) and theoretical intensity ratio curve as function of electron 