depending what router you have you can log into the router
To do this
First take a look at the Router and see if it hase this functionality and instuctions on how to log in should be printed on the router with an ip address which you type into your web browser, usually 192.168.1.1
Then plug yourr pc directly into your router and type in the ip
once you have entered the login details, you should be able to find the option to change the password (or google the make of your router and look up some youtube videos)
Let me expand on Henryutt's answer. If you are using an office network, it is owned and controlled by the company whose office it is. So, if you are an employee and a legitimate user, ask for the appropriate password.