One should use this method with care as artificial cross peaks will appear for uncoupled signals with excessive t1 noise. Before symmetrization, one should look for the smallest real off-diagonal signal. Make a mental note of the signal. Symmetrize the spectrum and then scale it such that the smallest real off-diagonal signal noted above is the smallest signal in the symmetrized spectrum.
On a Bruker spectrometer one can symmetrize the data with the commands "sym" and "syma" for magnitude and phase sensitive data, respectively. On a Varian spectrometer the command is "foldt".