General synonyms:
* Procedure: A series of actions taken to achieve a specific end.
* Method: A way of doing something, especially a systematic or established one.
* System: A set of interconnected parts that work together to achieve a common goal.
* Operation: A series of actions or steps performed to achieve a desired result.
* Technique: A way of doing something, especially a skilled or efficient one.
* Workflow: The sequence of steps involved in a task or project.
More specific synonyms:
* Treatment: (for medical procedures)
* Manufacture: (for industrial processes)
* Transformation: (for processes that change something)
* Evolution: (for natural processes of change)
* Development: (for processes of growth or improvement)
The best synonym for "process" will depend on the specific context in which you're using it.