google cloud platform – Can I manually adjust _PARTITIONTIME for historical data ingestion in BigQuery?

Duplicate of Big Query specify _PARTITIONTIME when inserting from one table into another

Partition in BigQuery can be updated. Google Documentation

Say for eg, I want to change the Partition to Monthly

CREATE TABLE IF NOT EXISTS `schema.data_monthly`
(
  name          STRING,
  id            STRING,
  publish_time  TIMESTAMP
)
PARTITION BY DATE_TRUNC(_PARTITIONTIME, MONTH);

INSERT INTO schema.data_monthly (_PARTITIONTIME, name, id, publish_time) 
SELECT DATE_TRUNC(_PARTITIONTIME, MONTH), name, id, publish_time
FROM schema.daily_data;

Now the partitions would be changed. Also If I try to give a wrong DATE_TRUNC function over WEEK, Big Query Will Error

INSERT INTO els_weather.pub_sub_weather_data_monthly (_PARTITIONTIME, name, id, publish_time) 
SELECT DATE_TRUNC(_PARTITIONTIME, WEEK), subscription_name, message_id, publish_time
FROM els_weather.pub_sub_weather_data

❗ Timestamp pseudo column for partitioned table only supports MONTH (in UTC timezone) granularity values