How to arrange the purchase and sale of an apartment for an office

How to arrange the purchase and sale of an apartment transferred to a non-residential fund for an office, but without reconstruction. I want to buy an apartment for a shop, and the fact that it has already been transferred to a non-residential fund suits me. According to the documents, she is still an apartment, and the sellers took the extract from the BTI. One of the notaries says that it is necessary to complete the design and reconstruction into an office, as planned, and only after the object is put into operation, documents are submitted for state registration, after which it acquires the status of commercial real estate that can be bought. But at the moment the apartment is in the process of re-registration (the current owners do not want to complete it because they are moving to another city), and although it has a registration certificate as a residential apartment, due to the transfer to a non-residential fund, the legal regime of real estate has changed , therefore, the sale and purchase may subsequently be recognized as null and void. The other notary sees no problems and is ready to formalize the deal. I would like to know the real solution.