how to update the company name after rebrand? and how to update address referenced on google maps?
it sounds you are about a business with brand "B1" at an address "A1" and the rebranded Business "B2" is now running form "A2"
If so the best you can do is reporting B1 at A1 as permanently closed and to create for "B2" at"A2" a new listing an verify it.
In case I misunderstood your issue elaborate it providen better details for both brands
Please include the following with your question:
1. Full business name
2. Current business address
3. Current telephone number
4. GoogleMaps Link or GoogleSearch link
Helmut Geissler, Google My Business Top Contributor | my G+ profile