Hi @spackmat, not sure that your question is on-topic to this thread. Sorry it got buried.
To accomplish this, you will need to edit the "path": on your manually created Service Definition to include the variable of your choice, and (if applicable) remove that parameter from the "parameters:" block.
If this does not sufficiently answer your question, I recommend you post a new thread with a copy of your Service Definition so the community can better assist you.