Linking PAN with Aadhar card in case of NRI

One of my clients staying in UK who does not have any place of residence in India, has received a notice from Income Tax department that if her PAN is not linked with her Aadhar card till 31-03-2023, her PAN will become inoperative. Being a permanent UK resident, she does not have Aadhar card. Can someone please suggest what needs to be done to keep her PAN active? Her registration in Income Tax portal has been correctly done as NRI with UK address.