How can we make the PLC work other works without changing item?

The answer is YES! PLC = Programmable Logical Controller Form the name itself shown that we can do programming or reprogramming the controller.
We can add or modify program during PLC is running.
I've been doing this for Allen Bradley PLC.
Note; you can add I/O module during PLC Run, you must stop PLC.
Configure the hardware and re-download the program to PLC

yes, we can edit programme for changing process.
   

i can't understand what do you need,can you ask this question by another way,olease? but,whatever PLC is reprogrammable devices (programmable logic control) ,it mean that you can change the software to be suitable for your task and change software several times   

what do you mean exactly? , sorry i did not get your question .

i donnot know your quastion but as i know plc cpu is microchip and this microchip have aprogram closed from the owener of the plc this program for compiling your application program to order for machine you can make some thing look like plc by programming microprosser look like (pic microcontroller , intel ......etc ) by this chip you can make your application on this chip  

I am breaking your question and reply as under: how can we make the PLC work other work? As I understand, "How we can reprogram the PLC to perform other process?", here we go Yes, you can reprogram the PLC to perform other controlling process.
Depend upon you requirement, and PLC design.
"Without Change Item?" What item it depends, if you are talking about, during the process, it is impossible.
You have to stop the process to reprogram the module.
If you are talking about field instruments, then may be but you have to read the Instruction and Installation manuals of your PLC, provided by manufacturer.

Of course we can, PLC is Programmable Logical Controller, it means we can do programming or reprogramming the controller. If you want to make a PLC work other works, according to your works or projects make something change on your PLC.

HI if your item is a machine that runs any of production, can add a2nd system as Siemens PLC, or modify the program (reprogram) PLC for a new job (depending on your plc) .

yes u can reprograme the plc using the software . And we no need to change the external connection we have to change only the programe thats is its main benefit , only one time wiring. 

Just reprogram your PLC but make sense about the I/Os of the systems

we can make changes in plc programming at any time as per the requirement of the machine for which plc is working we can add an additional i/o card or analog card

but after making changes u can download either hardware/software only or full download by stoping the plc in TIA s7 SIEMENS PLC's