How to Use Parent and Child flows in Power Automate

Introduction

Using Parent and Child flows in Power Automate is a best-practice approach for managing complex automation. Instead of building one large, hard-to-maintain flow, you break tasks into smaller, reusable components (Child Flows) that are triggered by a main workflow (Parent Flow).

This guide walks through a practical scenario—Automated Invoice Approval—to demonstrate how to set up flows, pass data, and return results effectively.

Why Use Parent and Child Flows?

Reusability - Build once, use across multiple flows (e.g., a reusable “Send Notification” child flow).
Maintainability: Fix bugs and update logic in a single, focused flow rather than editing a massive workflow.
Readability - Break complex logic into structured, manageable components.
Error Handling - If a child flow fails, you can manage the error without stopping the entire parent process.

Prerequisites

Before you begin:

Both flows must be created inside a Solution
The Child flow must use the “Manually trigger a flow” trigger
The Child flow must end with “Respond to a PowerApp or flow” action

🛠️ Practical Example: Invoice Approval Workflow

We’ll create a system where:

A Parent flow detects a new invoice in SharePoint
A Child flow handles the approval process

Phase 1: Create the Child Flow (Reusable Approval Logic)

1️⃣ Create a Solution

Go to Solutions
Create a new solution named: Invoice Automation

2️⃣ Create the Child Flow

Inside the solution, click: New → Automation → Cloud Flow → Instant
Name the flow: Child_InvoiceApproval
Select trigger: Manually trigger a flow

3️⃣ Add Inputs (Data from Parent)

Click “Add an input” in the trigger and define:

InvoiceID (Number)
InvoiceAmount (Number)
VendorName (Text)

These inputs allow the parent flow to pass invoice data.

4️⃣ Add Approval Action

Add: Start and wait for an approval

Use dynamic content from the trigger:

Example Title:

Approval Request - {VendorName}

5️⃣ Add Response Action

Add: Respond to a PowerApp or flow

Add output type: Text
Name it: ApprovalStatus
Map it to: Outcome (from the approval action)

✅ Save and exit.

Your reusable approval component is now complete.

Phase 2: Create the Parent Flow (Trigger & Orchestration)

1️⃣ Create the Parent Flow

In the same solution, click: New → Automation → Cloud Flow → Automated
Choose trigger: SharePoint – When an item is created
Select your Site and List

2️⃣ Add “Run a Child Flow” Action

Click New Step
Search for: Run a Child Flow
Select: Child_InvoiceApproval

3️⃣ Map the Data

Map SharePoint fields to child inputs:

SharePoint Column	Child Input
InvoiceID	InvoiceID
InvoiceAmount	InvoiceAmount
VendorName	VendorName

4️⃣ Handle the Response

After Run a Child Flow, add a Condition:

If ApprovalStatus = Approved → Update SharePoint status to Approved
Else → Update status to Rejected

✅ Save and test your workflow.

⚠️ Crucial Tips & Best Practices

🔧 Fix “Run Only User” Errors

If the parent flow fails to call the child:

Open the Child Flow
Click Run-only users
Change connections to:
- A specific service account
- Or Use this connection

Avoid using “Provided by run-only user” unless required.

Conclusion

Solutions: Both flows must be in the same solution.
Trigger: Child flows must use the "Manually trigger a flow" trigger.
Connections: You must configure the child flow to use specific connections, not user-provided ones.
Response: If passing data back, use the "Respond to a PowerApp or flow" action.