You ask an important question carol3885. We want to help in any way that we can. You can find details here: https://www.verizonwireless.com/support/local-number-portability-scenario-guide/ Please scroll down and see, "Replacing your existing Verizon Wireless number with one from another service provider." Does this help?
How do I begin the process to port a number from VOIP to my existing cell phone and keeping my cell number?
If you port the VOIP number to your existing cell phone, it will overwrite your current cell phone number replacing the active cell phone number with the VOIP number.
If you want both numbers, you need to port the VOIP number to a new line of service and a separate phone.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.