You can simply load data, since the fields are the same it will automatically take care of the field mapping.
or Merge... I find it wise not to mess with an original file under circumstances, even if I want to Append data to one. Why take the chance of things not going as planned. There is no UnAppend tool. And as Shantonu Sarkar indicates, code examples can be emulated in each tool's help section. But, if that is all you plan to do, is those files, use the tool manually once, then you can get the code from the Results window and use it to create a more generic version of your workflow