So I had someone ask me today and thought I would share this to others that might have the same issue. After setting up or changing you password you have forgot what the pass was and didn't setup or don't have a machine designed with Recovery questions, pattern, or reset email. Or maybe you setup that as well and forgot. I will admit on my Hikvision machines I have no clue what the questions are let alone the answers anymore..
Well in the app, there is the Device Manager, click on that then click on the device, then click on the Pencil, then you can click on the Eye next to your password and it will give you your password. Now you will want to click back, Then click on Configuration Center, then click on Modify Device password. then click on the device, then put in old password and then put in the new and repeat the new. Once done it might kick you out and make you sign back in and now the Device has a new password setup and you can now log in Over WebUI again..
If your device is Remote you can change it just as stated above as long as you setup your device with P2P and your device is still connected to the internet.
Another way is VIA ASP however more people use AVP then ASP
How to change your Password from AVP
How to change your Password from AVP
Be Safe.