How to change IP address of router?

How do I change my public (external) IP address? I connect to wifi via router. I have static IP address. I dont wanna change IP address of only one device, but the address on which all my devices connect. Do I have to contact my provider because of that or can I change it somehow by myself?
 
The WiFi is controlled by your router, while the PUBLIC address of that router is controlled by the ISP. One technique is to power off your MODEM for at least 24 hrs and the just restart it.
 
Enter your router's IP address into your favorite web browser
Log in with the default username and password
Click on Setup
Choose Network Settings
Type in the router's new IP address under Router Settings
Click on Save Setting.
 
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