how to replace one unit model with other using mscript

I have about 200 unit models I have to open each model and replace it with some other model from other path except the inputs and output which will remain same. If I do this manualy one by one it will consume a lot of time. Therefore i need some commands to be used as mscript through which i can automate this process.

[Jan]

What are "unit models"? How do you open them? What has to be replaced? How do you perform the changes manually? What is "mscript"?