I use Approvals in Flow a lot to automate approval processes for my clients. I recently had one client request that the designated approvers be pulled from a SharePoint list rather than being added in the Flow itself. This would enable an end user to update the approvers rather than having to submit a change request for someone in IT to update the Flow.
Setting Up the SharePoint List
The first step is to set up the SharePoint list to hold the approvers. Use the "Custom List" template and create an additional column called "Approvers" which is a Person or Group Field Type. Make sure to select the option to "Allow Multiple Persons" when setting up the field if you need multiple approvers.
Configuring the Flow
Now that we have our approvers list we need to configure the Flow. I used the "When a New Item is Added, start Approval" Flow template for my SharePoint list that I need the approval process on. After the "When a New Item is Added" trigger, add an "Initialize Variable" Action. Call this variable "Approvers" and set it to a string data type.
Next, we need to add a "SharePoint - Get Item" Action. Point this to the URL and list name of the SharePoint approvals list we created earlier. This action requires the ID of the item that you want to get from SharePoint so you'll need to put in the ID of the corresponding approver item.
Now that we have our approvers item, we need to insert a "Set Variable" action and set the Approvers variable we created earlier to the "Approvers Email" field from our Get Item action. Once we do that, Flow will automatically wrap the set variable action inside an Apply to Each function because the Approvers field in the list is set to allow multiple. The important thing to note here is we need to make sure to put a semicolon after the Approver Email field in the Set Variable action. If you don't do that then the multiple approvers will be strung together and the Flow will error out. The semicolon seperates the multiple emails and ensures they are registered properly.
The last step is to set the Assigned To property in the Approval action to the Approvers variable we just set. That's all you have to do! Now an end user can update the approvers in SharePoint without ever having to touch the Flow!