Yes, it is possible without modifying polystep() or polysys() . However, doing so would be a Bad Idea that would interfere with using input() for other purposes: You would have to replace MATLAB's input() function with a different function that took note of what prompt was passed in and used it to decide whether to make a real input() call (and memorize the results) or else instead pull back one of the recorded values. The code would have to be aware of what the form is of the prompts for the two different functions in order to be able to figure out whether the prompt it was passed should be treated as a new request or else to return one of the previous values that it memorized.
I recommend against this approach in any form.
Instead you should modify your existing functions to only prompt once and then pass the results around as needed, the way that @Bhaskar R shows.