How to migrate Google Apps accounts from one domain to another?

The e-mail domain administrator at some point in the time, may need to migrate a Google Apps account to another account managed with Gooole Apps, in the same domain (eg from pippo@esempio.COM to pluto@esempio.COM), or belonging to a different domain (eg from pippo@esempio.COM  to  pippo@esempio.IT)

There are at least two solutions to solve this problem:

1) use an e-mail client
For example with Thunderbird, you can create links to two accounts (source and destination) by choosing IMAP access. Then you can move all the emails from one account to another working on a folder at a time.
The process can be very long in terms of time (and boring) especially if your internet connection is slow and you have many mails to be move! In addition, calendars, address book, contacts and documents in Google Drive must be migrated by other processes.

2) use a third-party software
Specifically, it is Backupify MIGRATOR for Google Apps that may transfer all safely and automaticallyGmail Messages, Google Drive Docs, Contacts address book and calendars from one account of  Google Apps to another. 
It 'a paid service but to prove you have available 1 FREE migration!
Simply login with domain administrator credentials, and if you must have access to a second domain you must use its administrative account. Then you choose the source account and the destination account, so you begin the process!

[Source Link] Backupify MIGRATOR

The advantage of Backupify Migrator is that once you start the process does it all without the need to have your PC switched on or to check their work.