Separate gst no require for trading business- proprietor already engaged in rental service provider

Dear Sir,

Proprietor already engaged in Rental Service of immovable property (Providing commercial building owner) and already registered in GST as a service provider in his own name. 

Now he started a wooden furniture busiess as a trader and also having a Firm Name as proprietory business. Now my question is separate GST no require or he can amend his earlier GST number where he is a service provider and the GST no is issued to his personal name and he can change to personal name to Firm Name.

Please help. ??