There are a few steps involved, but for your clinic it's mostly just some initial forms to fill out, and then we wait for the various companies to go through their procedures.

Each provider will have details on porting a number out of their system.

On our side we work with a company called Twilio, and for their process we'll need a few things:
  • The authorized user or owner’s first and last name.
  • The corresponding service address. This must be an actual physical address. PO Boxes are not valid addresses.
  • A Letter of Authorization (LOA) signed by the authorized user and/or owner of the number(s). Note that the information on your LOA must match the authorized user name and service address provided by your current carrier: (Download the letter here: https://twilio.zendesk.com/hc/article_attachments/5150940275355)
  • Customer Service Records (https://help.twilio.com/articles/223179408-How-can-I-obtain-a-CSR-)
  • A scanned (or electronic) copy of the most recent phone bill, within the last 30 days, that includes the account, owner/authorized user name, and address information
Once we have all of that, we submit the request and wait for a while. The timeline seems to generally be one to four weeks depending on various things that (apparently) nobody can control. (If you really want more details, here's how Twilio describes the process: https://help.twilio.com/articles/223179348)