If something is waiting on a response either from a customer or a colleague, we would set the status to ‘awaiting response’. It would be helpful to have an automation that notifies you if something has been in that status for over a certain amount of time. E.g. if we have been awaiting response for 7 days, then notify somebody so they can send a chasing email. We would require it to work on subitems too.
There is an automation says something like notify someone if status is _____ so many days after due date.
Hi Mary-Kate,
Welcome to the forums first of all! 
One way for you to solve this would be the following two automations. I will describe the principle for you first. The first automation sets a date column to today, when your item changes to “Awaiting Response”; We need this date so we know when 7 days have passed.
This brings us to the second automation, this automation will trigger 7 days after the date we set and the status is “Awaiting Response”. We can then set the action to notify the person who is assigned in the Owner column.
These automations also work for subitems.
Hope this helps! 