Scheduler for reconciliation

Hi,

I am having 2 indices transaction and event.

transaction doc:

POST transaction/_doc/1234
{
"status": "Initiate",
"payload": "data",
"correlationId": "1234"
}

event doc:

POST event/_doc/1
{
"eventStatus": "Delivered",
"correlationId": "1234"
}

I want to create some scheduler/watcher which will reconcile these data after 6 hours and update transaction index based on event, like below:

After 6 hours when reconciliation will trigger then transaction document will change it to -

{
"status": "Delivered",
"payload": "data",
"correlationId": "1234"
}

Please let us know your inputs on this.