Tax invoice

Sir

can a reseller raise a tax invoice without having stock in physical. 

Eg: Customer goes to a shop and order for a Tv and shop keeper (reseller ) raises tax invoice and says he will need to order to his vendor and tv would delivered in four days time. In such a case, reseller actually donot have stock but raises tax invoice and issuing it to customer . Is it correct ? can a reseller raise invoice for a stock which donot have at the time of raising invoice ?