Texas Instruments TI-83 PLUS - Manual (Page 211)

TI-83 Plus Tables 208
3. Press Í . The cursor moves to the bottom line. Edit the function.
4. Press Í or † . The new values are calculated. The table and the
Y= function are updated automatically.
Note: You also can use this feature to view the function that defines a
dependent variable without having to leave the table.