Invitation Problem

On the information card I forgot to put the time that the reception starts. The place where we are having our reception will not be ready until 7:00pm. Any inexpensive ideas of how I can fix this.

What color are the invites? If you can find the exact font - maybe just make a small sticker with the time? OR actually, scratch that - how about just printing up another card to insert that 'Reception to start at 7:00pm' - guests will just get another piece of paper in it.

Good luck!