You can edit a client's info directly in MailChimp.
To edit a contact information in Mailchimp, follow these steps:
Step 1: Log in to your Mailchimp account and go to the Audience tab and click "All Contacts"
Step 2: Find the contact you want to edit, and click on their email address.
Step 3: In the contact details screen, make the necessary changes to the contact information and click the "Save" button to update the information.
Note: The specific steps may vary depending on the version of Mailchimp you're using.
https://mailchimp.com/en-ca/help/update-a-contact-profile/
If you need help with this, reach out to support at help@thevipclub.io.