General:
* Functioning
* Running
* Working
* Active
* In use
* Performing
For specific situations:
* Managing (for businesses)
* Conducting (for activities)
* Executing (for tasks)
* Carrying out (for plans)
For technical situations:
* Running (for software)
* In service (for equipment)
* Operational (for systems)
Example:
* Original sentence: The company is operating at a loss.
* Synonymous sentence: The company is functioning at a loss.
It's important to choose the synonym that best fits the meaning and tone of the original sentence.