I can travel from there to here by disappearing, and here to there by reappearing. What am I?

Why this works

This riddle plays on the movement of the letter 't' in the words "there" and "here." When you take the 't' out of "there," it disappears, leaving you with "here." Conversely, when you add the 't' back into "here," it reappears, allowing you to form "there" again. This clever manipulation of letters highlights how something can travel back and forth in meaning simply by vanishing or reappearing!