Close the blind fully so all of the fabric is exposed. Loosen the screws on the mounting bracket and remove the shade from the top of the window. Lay it flat on the ground.
Untie the knot at the pull-cord's base and then slide free the plastic knob at its end.
Untie these knots at the base of each vertical row of cord and pull the cord through the plastic loops until all cord is removed.
Tie a new cord to each bottom loop and string it up the vertical line and through the top eyelets across the top. Leave about three free hanging free from the top. Gather the cords together and slide the plastic pull cord knob over them and secure with a knot. Rehang the shade.