AT&T 999-501-149 system manual Editing Data, Do this

EDITING DATA	Follow the instructions in the table below to change entries.
		To				Do this
	Change a character in a field		Move the cursor to the incorrect
			character and type another character
			over it.
	Add characters at the end of an		Press [ > ] after the last character
	entry		and type additional characters.
	Insert characters in an entry		Move the cursor to the first
			character you want to change and
			retype the entire entry from that
			character, (You cannot use [ Insert ] to
			insert a character between other
			characters.)
	Replace a long entry with a shorter		Type over the characters you want
	one		to change, then press the space bar
			after the last character of the new
			entry. The remaining characters in
			the previous entry disappear.
			For example, to change “Joseph” to
			“Joe”:
			1	Move	the	cursor	to “s”
			2	Type	“e“
			3	Press	the	space	bar.
				The letters “eph” disappear.
USING THE HELP
	For more information about any screen or prompt appearing on the monitor,
SCREENS	press [ F10 ] (labeled “Help”). A help screen that describes the screen or the
	prompt will appear.

To exit a help screen and return to your previous place, press any key. If you press a function key to exit a help screen, you will exit help and then perform the function of that particular function key.

10-4Quick Reference Guide to Entering and Editing Data.