i change my exchange server like exch1 to exch2, if i have more than 100 users . i need to know if there is a tool a can use to modify outlook auto

If these are mapi clients, you dont have to do anything, the profile will be automatically updated if you move the mailbox to another server. You havent said what version of Exchange you are running, but if 2007 and older, be sure to leave the first server up and running so the profile redirection works. If you changed the name of the Exchange Server, then that isnt supported. If Exch1 no longer exists, then set Exch1 as an alias in DNS for Exch2. If you are asking about something else entirely, please update the thread.

exchange 2010

If this Exch 2010, then the mapi connections all go through the client access server and if you have defined a client access array and its set correctly on the mailbox stores, then it will all work automatically and you dont have to do anything for the Outlook profiles.