remove children property from json string in c#

I wanted to remove a children based on the parent property name. 

in My json string have parent and child and child has some other sub child. Here wanted to remove grand child. child name and grand child name is same so if i remove based on the name it will remove child and grand child. so if grand child has child as parent then remove grand child. appreciate your help. attached my json structure.  

Thank You!