Thank you for posting your query on Microsoft Community.
As per the issue description you are willing to change WIFI password of your Canon MG 2950 printer.
Before attempting to connect your PIXMA printer to your wireless network, please check that you meet the following two conditions:
Ensure that you have an access point (sometimes referred to as a router or hub) via which you get an Internet connection. Your access point must be fully functioning before you go to the next step.
Ensure that you have a computing device such as a PC, Mac, Tablet or Smartphone, from here on referred to as a computer, which is successfully connected to the Internet.
I would suggest you to refer the article mentioned below and see if it helps you to change the WIFI password.