code: @PUT
      @Consumes(Servlets.JSON_MEDIA_TYPE)
      @Produces(Servlets.JSON_MEDIA_TYPE)
      @Path("/uniqueAttribute/type/{typeName}")
      public EntityMutationResponse partialUpdateEntityByUniqueAttrs(@PathParam("typeName") String typeName,
                                                                     @Context HttpServletRequest servletRequest,
                                                                     AtlasEntityWithExtInfo entityInfo) throws Exception {
          AtlasPerfTracer perf = null;
  
          try {
              Map<String, Object> uniqueAttributes = getAttributes(servletRequest);
  
              if (AtlasPerfTracer.isPerfTraceEnabled(PERF_LOG)) {
                  perf = AtlasPerfTracer.getPerfTracer(PERF_LOG, "EntityREST.partialUpdateEntityByUniqueAttrs(" + typeName + "," + uniqueAttributes + ")");
              }
  
              AtlasEntityType entityType = ensureEntityType(typeName);
  
              validateUniqueAttribute(entityType, uniqueAttributes);
  
              return entitiesStore.updateByUniqueAttributes(entityType, uniqueAttributes, entityInfo);
          } finally {
              AtlasPerfTracer.log(perf);
          }
      }
docs: *****
  Entity Partial Update - Allows a subset of attributes to be updated on
  an entity which is identified by its type and unique attribute  eg: Referenceable.qualifiedName.
  Null updates are not possible
  *****