No Message will be sent to ... here it means when you withdraw an invitation, the recipient won't be notified about it.
When we invite someone, the person gets an invitation email, but when we withdraw an invitation, the person does not get any notification or email.
From the Help Centre:
(See the second point of the fifth point.)
You can withdraw an invitation if the recipient hasn't taken any action.
- Click the Inbox icon in the top right of your homepage.
- Click Sent on the left.
- Find an invitation without "Accepted" next to the name.
- Click the subject line of the invitation.
- Click Withdraw.
- If the Withdraw button isn't there, the invitation can't be withdrawn. It may have already expired.
The recipient won't be notified about a withdrawn invitation.
- If you change your mind, you'll need the recipient’s email address to send them another invitation.