How can I pull back an email that has already been sent?

Is there a way to invalidate (or pull back) this email and the attachment remotely?

Normally no.

However, some email services have a short window when you can "recall" mail:

• gmail - 30 seconds maximum - during which you can cancel sending email(s) (so it's not a true "recall")
• outlook - you can un-send email in Outlook only if that email is internal (both you and your recipient have an Office 365 or Microsoft Exchange email account in the same organization) and it hasn’t been viewed yet.
• yahoo - not possible
• AOL Gold (and AOL Mail in general) no longer offer this feature

In a practical way, no.

The situation is analog to regular mail. Once you drop a letter in the mailbox, it is pretty much gone. Now, not discussing the legal aspect, in principle you could remove the letter from the mailbox until the time the truck comes to pick it up. After that, you could somehow stop the truck, and the same with different parts of the delivery process. But it would require, even in the best of cases, good timing and a little persuassion. Lastly you could also get the letter from your recipients mailbox before they open it.

In the electronic case, the situation is similar. After you send an email it usually passes from server to server (usually at least two), and it stays at the destination server until the client checks their email. In principle, again, you could stop the process at any time by deleting the file from the corresponding server before it is sent to the next one. Thing is, most of the time this happens fairly quickly (seconds, although in some cases it could be hours and sometimes even more in the past). And in general you don't have access to any of the servers involved.

Summary: technically possible, during a usually short window; basically impossible in practice.

I know there is a way to invalidate an attachment sent along with the email, but not sure about the email itself.

This, also isn't true. Attachments are just encoded in a way that allows the email system to transfer them, but they are carried within the same message. This would be different if you don't actually attach the file, but instead upload the file to some separate server and only send a link. This could be as simple as an HTTP server and an URL to the file, or it could be something done by a more sophisticated document control system.