Joining a new practice doesn't require a new National Provider Identifier.
I am a single provider who is joining another practice. How do I go about getting a new NPI specific to that practice?
A new NPI is not required. You will always bill with that single provider identifier. It will be necessary to notify NPPES (National Plan and Provider Enumerator System) within 30 days of your new address, tax ID number, and the effective date of the change. CAQH (the internet-based credentialing website that most insurers use) will have to be updated as well. Most insurers routinely download provider files to update their records. Information you will have to provide includes your new address, tax ID, W-9, malpractice face sheet, and effective date.