What type of acknowledgment does the third party system send?
That aside, you will need to create a 997 from the 270 you receive.
However, understand that the purpose of a 997 is to tell the sending partner whether or not the transaction they sent is properly structured.
That is normally done by the receiving partner – you are not the receiving partner you are the intermediary.
There is a provision for the intermediary to respond in the X12 standard.
You should have in your possession an Implementation Guide for the 270/271 Transaction set as well as 2 Companion Guides (wll at least one since I don’t know what the thir party partner in your scenario’s function is).
Among all of the three guides is supposed to be sufficient information for you to determine what the transaction sets and acknowledgments require.
Also in there should be a description of how intermediary bodies can respond.
There is also a TA1 transaction set that can be returned to a sending system.
Even if the receiving system did provide a 997, I am finding out that routing replies in the current releases (5.x) of Cloverleaf(R) does not seem to work. I think it is a bug as I recall routing replies fine in 3.3.1 but I am told that this is the way it is designed to work. So assuming the receiving partner did send you a 997, I am not sure how you would route that back to the sending partner if you wanted to.