Unable to update Template for a VM

My aim is to update or overwrite the START_SCRIPT specifically in the Template of the VM but I am facing some issues

The START_SCRIPT is initialized with some values while deploying the VM.
Opennebula version: 5.10

  1. one.VM.update
    I tried this api but only the START_SCRIPT in User Template is being updated, which doesn’t have any affect on the VM’s START_SCRIPT

  2. one.Template.update
    Getting the following error while using this api. Since the START_SCRIPT is present in Template, we thought of using this.

  1. one.VM.UpdateConf
    Since the START_SCRIPT is in Conf, we tried to use this api but couldn’t get the desired result. After running the api no change took place.
    According the docs it appends the attributes but we want to update / overwrite them.

Now, what can I do to Update the Template for the VM which has some attribute initialized ? We have tried what we could think of but we are unable to figure it out.
We only have finite IPs so we don’t want to delete the VM and deploy another.

Note: Tried the above apis while VM was shutdown and active state but couldn’t change the attributes in Template.