If you need to do something in the database based on an interval, you cannot execute the code in a trigger since trigger is executed immediately upon the data manipulation.
Taken this is SQL Server, you can use SQL Server Agent - SQL Server Agent | Microsoft Docs
] to execute code on a regular interval and update the rows you want.
If you're using SQL Server Express Edition, SQL agent is not available. In that case you could use for example SQL Agent: A Job Scheduler Framework
You also probably need to add a column in your table to distinguish the records that have been updated from those not yet updated...