从PHP中的DLL文件调用C＃函数

I'm wokring on a PHP webapp which is using a web service from a third party. My app stopped working after the third party made some changes to their web service. They now wrote me that all I have to do is call the function "SetURL" and set another url, a new one they started using.

The function exist in a DLL file that has been made by the third party. This is the SetURL function they told me to call and set another url than the pre existing one.:

My problem is, I am not aware how to call an function from a DLL file in PHP and execute it. I have never worked with DLL files before.