What if you only own part of the building?
If the whole building shares one heating system then it needs one EPC and this can be used for any part of the building sold or rented.
If it has separate parts with separate heating systems then an EPC should be made for any part offered for sale or let.
If a building has a common heating system and you own part of it, then the landlord is obliged to provide an EPC for the whole building.