As long as you have written agreement from your client acknowledging and/or agreeing to the change in the contract, you can actually process the ad size increases from your end. Please note, though, that decreases, must go through Support.
Here is a tutorial on how to upgrade an ad size:
How to Upgrade an Ad Size
https://embed.app.guidde.com/playbooks/rGsxmuKzsYJN1xEwFAg7xd
This guide will walk you through upgrading an ad size in ARC
Go to citylifestylehq.com
1. Upgrading an Ad Size
Upgrading an ad size can boost visibility and enhance the effectiveness of the client’s message by providing more space for content and creativity. It can also strengthen client relationships and improve retention by offering additional value, demonstrating the publisher’s commitment to the client’s success.
2. Reporting Page
In ARC navigate to the Reporting page on the left hand side
3. Generate the "Ad List" report
Select the report titled Ad List from the drop down menu
4. Click "Display"
Click display to generate the report
5. Select client's insertion
Locate the client you are wanting to upgrade the ad size for. Select their insertion under the Design column
6. Select the upgraded ad size
Select your upgraded new Ad Size from the dropdown list. Note that the ad sizes listed here are the only ad sizes available.
7. Update ad cost
Input your updated ad cost. It is up to the publisher to decide how much the upgrade will cost. Some do it as a one-time selling tool in hopes that the client will want to upgrade permanently. Others do it as a selling tool to show the client what an upgraded Ad could get them, usually associated with a fee for the upgrade cost.
8. Click "Update" to upgrade that month's insertion
Click on the "Update" button to apply changes. Note that this will only upgrade the month's insertion that is selected. The next month and the rest of the contract will be at the original contract size, unless the Publisher makes it a permanent upgrade.
9. Requirements
The upgrade must be performed before the creative deadline. The insertion can only be deleted if no ads or materials have been uploaded. If materials were already uploaded you will need to submit a ticket to remove submissions
This guide walked you through how to upgrade an ad size in ARC.