Doubt in pan card application

Hi friends!! I had a doubt with regard to pan card application.

I have a client company say " X private limited" incorporated on may 2013. The name was changed to " Y private limited" and then "Y private limited" is changed to "Y limited" (i.e.) a public limited company and got certificate of incorporation for "Y limited" .I have applied and got pan card for "X private limited" on may month itself. Now my query is whether i should apply for a new pan card for "Y limited" or should i apply for changes in pan card for "X private limited". What are the procedures?

Thanks in advance!