Authorised capital reclassification

Dear All,

The company is having Authorised capital of Rs. 15 Crore 1.5 crore equity shares of Rs. 10/- each and company wants to issue the preference shares is it necessary to increase capital as a authorised capital for preference shares?

and if company dont want to increase the share capital of 15 Crore can the company go for classification aur what can be the way out for the same and what will be the procedure of reclassification its a pvt ltd company.