From my questions with customer service all you need to do is go to the home page at visible.com or the Visible app and select the plan you want and a new SIM card will be sent to you for the new plan you select. I am waiting to switch until they make us to save money since it is cheaper staying on the party pay.
One other thing I should point out is I don't think I have had any luck with the app and there is a problem with visible.com also erroring out when I am on my Overview page and click the button under "A better network is waiting" and I click on the "see new plans button" and when I select the plan I want it errors out. But, to get around that if I click the drop down menu for plans at the top and select check our plans, click bring my phone, click the check phone compatibility button, select your phones software(either iOS or Android) and run your phone then select the plan you want if phone is compatible you can proceed to order it that way. FYI, if you have an android phone it would be my suggestion to get a physical SIM card because from what I have read eSIM doesn't work on android and on iPhone it is hit or miss.
The app worked switching plans on my wifes iphone, but refused to work on my android, it has to be a known issue at this point, but there is no fix afaik. The work around involves something the care team does to tee up the change and you complete it via the app or website. Took about 6 hours of chatting email and sending them screenshots by FB to get it resolved. The weird thing is that the plan change apparently requires a new Sim or esim, I can't think of a good reason why. Good Luck.
From what I gathered from my communication with support and reading different articles and posts here is that the system is being changed from cloud based to what Verizon is currently using to power there system. From what I gather it takes a new card that is programmed to the new system. I may be wrong but it is how I interpret it.