Clear the value of "Parent Link" field when creating a new issue

[Abhishek Kalamkar]

When creating a new issue, I need to clear the parent field. Parent link should be empty. 

I have tried multiple options like 

{
    "fields": {
        "parent": null  
    }
}

and 

{
"update" : {
"Parent Link" : [{"set": []}]
}
}

does not seems to work. 

can you please help to sort the issue out. 

[Mesut Yilmazyildirim]

You need to write or find a plugin to do that.

We are using Jira Misc Custom Fields