Open the blinds by pulling down on the cord.
Remove the clips on the brackets that hold the problem blind in place.
Remove the bottom bar and any clips that support the blinds cord and ladder strings. The ladder strings hold each blind in place, so it's possible to pull out the problem blind. You may need to cut the two ends of the cord at the bottom of the bar with scissors or a knife, depending on the blinds' design.
Pull the ladder strings up to the head part of the blind and remove the malfunctioning ladder slats.
Insert new ladder slats in place of the problem slats where the old ladder slats are placed.
Pull the old ladder string all the way up until it loosens and is totally removed. Insert the ends of the new ladder strings along the top, on the pulleys and along both sides of the ladder slats.
Tie the lift cords to secure the blinds. Reach for the bottom bar and replace it.
Hang the repaired Venetian blind.