Delete One-to-One DataObject android

I want to delete child Object which has one to one relation with parent object

I am updating Parent Object which has relation(one-to-one) with child1 and child 2 object,
So before Update I get parent Object and load its related data child1 and 2.
but now while making update request I want to delete child 1 object (which has relation with ParentObject) ,
So I just set Parent.setChild1 = null; and make update request with updated Parent object. but what I see is that object is still there. Please help me.

You can not delete objects by updating relation, in this way you can only break relation.

To delete object you have to call

Backendless.Persistence.of( SomeObject.class ).remove(  someObjectInstance );

This is not efficient I have to make Two Call first to break link and then to remove object

Bye the way using my method It doest even break the relation I still get Object on Retrival

just remove object, link will be breaked

I dont have list I have single object relation so I cant just remove Object In java I guess

I am passing null but its not working