cloudHQ can migrate all messages from one Gmail account to another, preserving labels, dates, sender information, flags, and other metadata. It ensures that emails sent to your old account are replicated to the new one, allowing uninterrupted use of your old email address during migration.

cloudHQ can migrate all messages in a label from one Gmail account to another. This support note explains how to do it:

1. Start wizard here: https://www.cloudhq.net/migrate/gmail/gmail
2. Select source account and label
3. Select target account and label
4. Start the migration