Thanks a lot for your reply. I'm sorry for the vague question.
My question was based on my result that if I take "default" value lifc = False, I got incorrect phonon dispersion but a correct dispersion with it being true.
So, I don't quite fully understand that how the phonon wannierization is done without reading the force constants from q2r output (isn't it calculated using eigenvectors of the dyn matrices for the transform?) and why was I getting incorrect result with default value.
Thank you so much for your time and help.
General discussion around the EPW software