What I mean in change of symmetries is non centrosymmetry to centrosymmetry within the same structure or different structure. What I mean about structural change is centrosymmetric structure (eg orthorhombic,centro) to another centrosymmetric structure ( eg cubic centro). In this two cases can we observe dielectric anomaly at particular temp.

If any one having good reference regarding this please attach. It may be helpful to my understanding purpose.