There is a threaded adjusting sleeve that connects the inner and outer tie rods. It has a right hand thread on one end and a left hand thread on the other end. During an adjustment, when it is turned it acts like a turnbuckle. Turning it one way shortens the tie rod assembly. Turning it the other way lengthens it.
Adjusting sleeves resemble a piece of internally threaded pipe. They have a slot or separation that runs either their entire length or just part way. Adjusting sleeves also have two crimping or squeezing clamps located at each end to lock the toe adjustment.
Badly rusted, worn or damaged adjusting sleeves should be replaced.