AT&T 6300 Programmer's Manual page 242

EDIT
Command
Syntax
linenum
Remarks
Example
7-86
Lets you change a program line. ED IT is only
used in immediate mode.
EDIT [linenuml.l
is the program line number. If no such line exists, an
"Undefined Line number" error message is displayed.
A period can be used instead of a line number to refer to the
current line.
When you enter an EDIT command,
GWBASIC displays the specified line and
positions the cursor under the first digit of the
line number. The line may then be modified by
using the special editor keys.
The EDIT command can be used to redisplay
and edit a line which has just been entered.
(The line number symbol "." always refers to
the current line.)
LIST may also be used to display program
lines for editing.
EDIT 500
500 PRINT AS,BS,CS