HR is one of the key aspect of post-merger integration. In fact, every aspect of the integration depends on people (HR) and therefore it is imperative to involve HR at the very early stages in the M&A process, bearing in mind that communication is crucial in achieving a successful M&A transaction.
I would not recommend that your HR travels to the acquired company to address individual concerns. Instead, concerns should be addressed holistically in line with the corporate objective for the new firm.
