[multisite] How to trigger metadata sync update?

Hi folks, I desperately need some help to figure out how to trigger metadata sync update in a multisite environment. I'd like to change any data item in RGWBucketInfo at the master zone and want the other zones to pick up the changes. I have tried to use rgw::sal::Bucket::put_info() and RGWBucketCtl::store_bucket_instance_info(). Either approach only updates the local bucket info and the other zones do not pick up the updates. What am I missing? Could someone please show me an example on how to trigger sync update? Thanks a lot, Yixin