If you're going to port your number to any particular carrier, you simply contact that carrier to which you are porting. You provide your current account information to your new carrier and they would then contact the original provider and request the number. In this sense, you don't actually need to contact the original carrier, but you would
SAP Help Portal SAP Help Portal Download PortQryUI - User Interface for the PortQry Oct 23, 2019 Port numbers, URLs, and IP addresses | Deep Security
Service Name and Transport Protocol Port Number Registry
Porting Your Mobile Phone Number | Tips & Tricks – Canstar Keeping your phone number has obvious benefits — it eliminates the need for notifying your contacts about the number change and memorising a new number. In order to keep your number when you switch providers, you’ll need to ‘port’ your existing number.
After installation, you can change the port. You don't have to use the same port number throughout the site hierarchy. If the HTTP port is 80, the HTTPS port must be 443. If the HTTP port is anything else, the HTTPS port must be 1 or higher, for example, 8530 and 8531.
Email Ports – POP3, IMAP and SMTP Port Numbers Aug 29, 2016