It is better to contact the Dircector Factories of your state or discuss with the Factory Inspector of the area where your units are existing to get the details.
For your information to have single licence you have to cahnge :
a)Factory lay out
b) bring the both factory within one boundary
c) Fix one name for both the units
d)You have to fix one person as a manager for both the units but occupier would remain same.
e)You have to notify such cahnges in large scale to all ..................and many more things
18th January 2019 From India, Mumbai