OK, there is much more information, but some things are still not clear.
1. I want to titrate acetic acid and Ammonium sulfate seperatly.
I take it you want to determine concentrations of acetic acid and ammonium sulfate solutions by titration, right?
2. Then i want to mix both to make standard solution and titrate that mixture.
What reaction do you want to use when titrating the mixture? Acetic acid and ammonia in such mixture can be both titrated with strong base, but I have no idea why do you want to mix them and titrate - if you know exact concentrations of both solutions from the step 1, and if you use graduated glass for mixing, you will have quite good control of the concentrations in the mixture. Or am i completely off and you want to do something completely different?
3. Up and down titration: Up titration is done when sample were acidified with HCL to pH 2, for downtitration pH adujusted to 12 and then titration is done. What is the purpose of this, i want to know. I read this i an article that is why i want to do, why this kind of titration done and what result we get.
How is this procedure named in your native language? And, again - what are reactions that take place in these titrations? There is a slight chance that you mean
back titration, but I don't find this idea very likely.