Json Patch - attempt to update attribute of an nested object is not happening.

[prats2017]

I am trying to assign new dept to Employee using deptNameusing JsonPatch but the update to DB is not happening. I noticed that my patched object has Dept object has new/updated name but no is still pointing to old deptNo. Looks like Patch is attempting to update dept.deptName instead of updating reference to entire dept entity (which I think should be the case). what am i missing here?

[{"op":"replace", "path":"/dept/name","value":"HR"} ]

@entity
public class EMP{
@manytoone(fetch = FetchType.LAZY)
@joincolumn(name = "deptNo", referencedColumnName = "deptNo")
private Dept dept;
}

@entity
public class Dept {
private String deptName;
private Integer deptNo;
}