Remapping rostopic from the existing ReadOnly launch file

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I have an RPLidar and I installed the necessary packages. Right now, the laser data is published to the /scan topic and I can see the output from Rviz.

I have another project and I should use this implementation for that: https://github.com/praveen-palanisamy...

Now, the problem is: I should publish the scan data to the filtered_cloud rostopic but I could not figure out how.

I have read about remapping but the problem is:

The src folder and rplidar.launch files are ReadOnly.

The rplidar.launch is:

<launch>
  <node name="rplidarNode"          pkg="rplidar_ros"  type="rplidarNode" output="screen">
  <param name="serial_port"         type="string" value="/dev/ttyUSB0"/>
  <param name="serial_baudrate"     type="int"    value="115200"/><!--A1/A2 -->
  <!--param name="serial_baudrate"     type="int"    value="256000"--><!--A3 -->
  <param name="frame_id"            type="string" value="laser"/>
  <param name="inverted"            type="bool"   value="false"/>
  <param name="angle_compensate"    type="bool"   value="true"/>
  </node>
</launch>

This file and the folder in it are ReadOnly how am I going to remap the /scan points to the filtered_cloud? Can you please give detailed instructions for that?