HP-15C time calculating program

[lomchivok]

I have a thermal cooking process for canned salmon that needs to be timed for a specific amount of time.
The process time is 4 hrs and 34 min.
I have written a program that calculates the cook time correctly but displays the calculated process time in 24 hour format ie. 12:00 start time and 4 hrs and 34 min later it is done cooking at 4:34 but displays 16:34.
I need a subroutine that takes the integer and subtracts 12 from it if the integer is greater than 12 and displays the calculation in 12 hour format.
Here is my program that calculates the process time in 24 hour format.
F LBL A
G>H
STO 3
4.57 (= 4 hrs 34 min in decimal hours)
ENTER
RCL 3
+
F >HMS
Sto 2
G RTN
Any help would be much appreciated