Hello @Ala,

Thank you for sharing your question with the Klaviyo Community.

Since Memberstack isn’t an integration Klaviyo currently supports, there isn’t a way for Klaviyo to control how the update to the email address is reflected on Klaviyo’s end. With that said, you can navigate to the profile within Klaviyo and manually update the email address (solution in the below thread):

or use the Identify method to update emails. Keep in mind by using a unique identifier with the $id key, you take on the full responsibility of identity management within your Klaviyo account. You must ensure that all calls are made mapping the right $id value you're setting to the right $email using the $id. 

You may also want to check with Zapier to see if they can assist further. Also looking forward to seeing if another member of the Community may have another solution based on their experience with Zapier or another 3rd party app.

Thanks for being a member of our Community. 

Hello and thank you for your response!

The $id method is exactly what I’m looking to apply. I already added an external ID to the klaviyo member, but when I perform a zapier action to search for a member, it seems it only allows me to search by email? (this is nothing to do with memberstack at the moment, but rather zapier-klaviyo facilities).

Hi @Ala,

Thanks for your response and clarification.

While Klaviyo allows 3rd party platforms to pass in the $id field to Klaviyo, it is not a field that we actively manage or control within the Klaviyo platform. With that said, it would be a great question for Zapier -- to understand if it’s possible to search for a member using an $id field. If this is not possible, I recommend checking out the Identify API documentation I linked above to update properties about users using the $id field as the primary identifier. 

Thanks and have a great day.