Can't edit email in 'To' option after Flow created

I've built several approval Flows in a Client's tenant. Most of them have an email being sent to a person based on a new SharePoint list item. But after creating the flow I can't edit or change the 'To' field or the email address. It has a grey background. I built it using my client tenant email address for testing so it is connected to that tenant. But I can't change it afterwards to the correct person.