Change the Name Field of Contacts

HI,

I collect only emails on my Landing Page. So initially, I only have these contacts’ emails.

Now my welcome email encourages them to reply back. Once they reply, I have their First and Last Names from the “Name Field” in their reply emails

Is there a way to Auto-Update these contacts names now that I have their First and Last Names after they’ve replied to my Welcome email?

thanks so much