rocky272727,
logically speaking, the answer to your question 'What reason are you giving for the changes?' depends on what the change is.
For eg., change to natural time progression is fairly straight forward to explain. whil submitting to CIO it was 5 yrs 3 monts; now while submitting to CHC it is 5 years 6 months.
Second category is addition of job responsibilities. Job duties might have changed in the last 6 months; and you might have got the letter. you can make the changes accordingly, and you can mention that recently the changes happened due to the new responsibilities that you were given at the organization.
And finally, if you have done a mistake; better admit it; and substantiate it with the proof (if possible).
Hope it helps.
Cheers Bolt-z-