### Discussed in https://github.com/apache/airflow/discussions/24548

<div type='discussions-op-text'>

<sup>Originally posted by **don1uppa** June 16, 2022</sup>
### Apache Airflow version

2.2.5

### What happened

I have a dag that starts another dag with a conf.   
I am attempting to start the initiating dag a second time with different configuration parameters.   I it to start the other dag with the new parameters.

## What you think should happen instead

It should use the new conf when starting the called dag

### How to reproduce

See code in squsequent message

### Operating System

windows and ubuntu

### Versions of Apache Airflow Providers

N/A

### Deployment

Docker-Compose

### Deployment details

_No response_

### Anything else

**Work around for now is to delete the previous "child" dag runs.**

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)
</div>
else:
            run_id = DagRun.generate_run_id(DagRunType.MANUAL, parsed_execution_date)
        try:
            dag_run = trigger_dag(
                dag_id=self.trigger_dag_id,
                run_id=run_id,
                conf=self.conf,
                execution_date=parsed_execution_date,
                replace_microseconds=False,
            )
        except DagRunAlreadyExists as e:
            if self.reset_dag_run:
                self.log.info("Clearing %s on %s", self.trigger_dag_id, parsed_execution_date)
                
                dag_model = DagModel.get_current(self.trigger_dag_id)
                if dag_model is None:
                    raise DagNotFound(f"Dag id {self.trigger_dag_id} not found in DagModel")
                dag_bag = DagBag(dag_folder=dag_model.fileloc, read_dags_from_db=True)
                dag = dag_bag.get_dag(self.trigger_dag_id)
                dag.clear(start_date=parsed_execution_date, end_date=parsed_execution_date)
                dag_run = e.dag_run
            else:
                raise e
        if dag_run is None:
            raise RuntimeError("The dag_run should be set here!")
        
        
        ti = context["task_instance"]
        ti.xcom_push(key=XCOM_EXECUTION_DATE_ISO, value=dag_run.execution_date.isoformat())
        ti.xcom_push(key=XCOM_RUN_ID, value=dag_run.run_id)