HP 35s Scientific Calculator - Manual (Page 215)

Programming Techniques 14-5
A Programmed GTO Instruction
The GTO label instruction (press  label line number) transfers the execution of
a running program to the specified program line. The program continues running
from the new location, and never automatically returns to its point of origination, so
GTO is not used for subroutines.
For example, consider the "Curve Fitting" program in chapter 16. The  
instruction branches execution from any one of three independent initializing
routines to LBL Z, the routine that is the common entry point into the heart of the
program:
Using GTO from the Keyboard
You can use  to move the program pointer to a specified label line number
without starting program execution.
   Can start here.
.
.
.
   1
Branches to Z001.
   Can start here.
.
.
.
   1
Branches to Z001.
   Can start here.
.
.
.
   1
Branches to Z001.
  
1
Branch to here.
.
.
.