Only users who accept the invitation can change their email address for security reasons. Here's a guide to it:
How do I change my email address?
If you invited a person with the wrong email address
If you invited a person with the wrong email address who did not accept the invitation (a blue button with an arrow appears to the left of the name), you can change the email address by clicking on the icon with three dots (···) on the right and selecting the option " Edit".
Change the email address and continue by clicking "Save".