"I welcome his offer, accept it, and will forward a formal invitation to him tomorrow."

Perhaps he could even extend a formal invitation to the house.

Then his people go and brief that a formal invitation has been issued.

It's a matter of whether a formal invitation will be made.

It was a formal invitation not just to collaborate but to make friends.

That day people visit to friends, relatives without formal invitation.

It was a closed meeting; those present had formal invitations.

The next spring, the formal invitation came to become a trustee.

On Friday, everyone got the formal invitation, complete with directions.

"Do we wait for a formal invitation to see where they live?"