How can I get my locally running app to see cookies from an app that is in production?

I have an Ember app in production & I have recently created a React application that will eventually replace the Ember app.

The plan is to begin migrating pages over into the React app.

For now, I'm just trying to login to the production app & then grab that cookie from the React app (locally - since it is early stages of dev) The issue that I'm currently struggling with is that I can't access the tokens/cookies from the production app because they are at my-domain.com where as the react app is running at localhost:3000

How do I go about sharing cookies & tokens between production & local?

Thanks in advance!