Texas Instruments TI-83 PLUS - Manual (Page 511)

TI-83 Plus Programming 508
Inserting and Deleting Command Lines
To insert a new command line anywhere in the program, place the
cursor where you want the new line, press
y 6 , and then press
Í . A colon indicates a new line.
To delete a command line, place the cursor on the line, press ‘ to
clear all instructions and expressions on the line, and then press { to
delete the command line, including the colon.