The POP password will be set/reset on the server itself. it is not something that you can do on the client.
If you are connecting to a corporate email server then you need to contact their support to establish how to change the password.
If you are connecting to an ISP's email server, then the ISP should have a system for changing the password.
Simon.
Hi,
As Simon said, changing the password is not something you can do on the client side.
You have to contact the server administrators.
In addiction, I have found the below article for your reference:
https://technet.microsoft.com/en-us/library/cc747462%28v=ws.10%29.aspx?f=255&MSPPError=-2147217396
Hope it's helpful to you.
Regards,
David