Agency handover checklist: what to transfer when you switch marketing agency

What should an agency handover checklist include?

An agency handover checklist covers five things: who owns each account, who has access, what was built, what was changed and why, and what is still running. Miss one and the new team starts by guessing.

Use this table as the base. Tick a row only when the client, not the agency, holds the item.

Two rows cause most of the trouble later. Ownership decides who can lock whom out. The change history is the only record of why the accounts look the way they do, and it is the first thing you need when results move in the weeks after the switch.

How do you check who owns each account before switching agency?

Check ownership and admin access on every platform before anyone is removed. The rule: the client keeps at least one admin seat of its own everywhere, and the agency only ever has delegated access.

Google Ads

• A client account can have only one owner manager account. Owner managers get full administrative and data access, but Google states that the client account still owns its data and can remove ownership by unlinking the manager.
• Client account users can't transfer ownership, but they can unlink a manager that has ownership. After that, the client can turn on ownership for a different manager, such as the new agency's.
• Google Ads has five access levels: "Email-only", "Billing", "Read-only", "Standard" and "Admin". Only Admin users can give access and change access levels, so a client employee must hold Admin before the handover starts.
• Payments profile users are handled separately: Google Ads users can't add or remove them directly, and the profile's primary contact has to contact Google Ads support. Start early if the agency pays the invoices.

GA4 and Google Tag Manager

In GA4, open Admin, then Access Management under Account or Property. Users can only be deleted at account level and by an Administrator, and the last Administrator can't remove themselves.

In Google Tag Manager, open Admin, then User Management in the Account or Container column. The account Administrator can change permissions. At container level, only Publish lets someone push changes live; Edit and Approve can't publish.

Meta Ads

Confirm that the ad account, the Page and the pixel or dataset sit in the client's own business portfolio and that the agency only has partner access. If the agency created the ad account inside its own portfolio, solve that first: the client can't remove the agency from an asset it doesn't own.

How do you keep the change history when the agency leaves?

Export it before access is removed and keep a copy outside the ad accounts. Platform history is limited and records what changed, not why, so the reasoning behind each edit leaves with the agency unless someone wrote it down.

In Google Ads, open Campaigns, then Change history, set the widest date range and download it. Ask the outgoing agency for its own log too: budget decisions, tests, tracking edits on the site, CRM changes and the reason behind each. The Google Ads change history guide explains what each entry shows.

Then keep one log that belongs to the client. A marketing change log owned by the client survives every agency switch. In Changeline you can connect Google Ads with a read-only connection: the first connection imports the last 30 days, changes then sync every 6 hours, and they stay for as long as the project exists. Meta, site, tracking and CRM changes are logged by the team. The options are compared in how to track Google Ads changes automatically.

What is the step-by-step agency handover plan?

Run the handover in three phases: prepare while the old agency still has full access, switch on a fixed date, then watch the first 30 days closely.

Before the switch (2 to 4 weeks)

1. List every account and asset: Google Ads, Meta, GA4, GTM, Search Console, CRM, landing page tools, feeds and scripts.
2. Give a client employee Admin or Administrator access on each one.
3. Agree a change freeze: from a set date, the outgoing agency only makes changes that are approved and logged.
4. Export Google Ads Change history, Meta activity history and the agency's change log.
5. Collect documentation: conversion actions and their definitions, audiences, automated rules, scripts and running experiments.

Switch day

1. Give the new agency access, then unlink or remove the old agency.
2. Log the handover itself as a change, with date and owner.
3. Check conversion tracking end to end before touching any campaign.

First 30 days

1. Make no structural changes in week one; read the accounts first.
2. Log every change the new agency makes, with the reason.
3. Compare results with the weeks before the switch and with the same weeks last year.

How do you find what caused a performance change after the handover?

Put every change from the days before the shift on one timeline, rule out tracking first, then test one hypothesis at a time. Handovers make this harder, because two teams changed things in the same weeks and neither sees the full picture.

1. Build the timeline: the old agency's last edits, the new agency's first edits, platform automations such as auto-applied recommendations, and site, tracking or CRM changes.
2. Rule out tracking: were conversion actions, tags or the GTM container edited during the switch? A removed tag or a new primary conversion looks exactly like a performance drop.
3. Match the date of the shift to the timeline and keep only the changes that came before it.
4. Test one hypothesis at a time, for example by reverting one change or comparing campaigns that were and weren't touched.

Example: leads fall 30% in the second week after a switch. The timeline shows that the old agency paused two campaigns on its last day, the new agency changed bidding on day 3 and a developer replaced the contact form on day 5. The form change came right before the drop, so you check it first.

For the full method, read marketing root cause analysis and the guide on how to explain a conversion drop to a client.

What mistakes break an agency handover?

• Removing the old agency before ownership moves. If the agency's manager account owns the Google Ads account and no client employee is Admin, nobody on the client side can fix access quickly.
• Assuming history stays forever. The Google Ads interface shows 2 years, the API 30 days, and Meta does not publish a period. Export first.
• Losing the reasons. Platform history shows what changed, not why. Ask for the decisions behind budgets, bidding and account structure.
• Editing on day one. Changes in the first week mix with the old agency's last changes and make every later diagnosis harder.
• Forgetting tracking. GTM, GA4 and conversion actions often stay with the agency's users. Without a client user with Publish permission, nobody can fix a broken tag.

Keep the client's changes on one timeline that every agency can read and add to, and the next handover starts with the full history instead of a blank sheet. You can start a free change log in Changeline.