How to politely reject an earlier onboard date?

Hi there,

You don't need to defend yourself!

Keep it short and sharp. Say you really wish you could, and are generally a team player, but just physically can't due to personal matters - say you would if you could.

That's it!

Hi there,

Q: Should I provide specific and concrete details to reject starting earlier? Or, is it reasonable if I propose onboarding according to the original schedule without giving specific reasons?

I would call HR and explain over the phone you have set a few personal appointments following the original schedule in a different location, so unfortunately that won't be possible. I don’t think there could be any issue if you clarify it in this way over the phone.

All the best for a great start!

Francesco

Hello!

Totally depends on your style. Both are valid, as long as you are kind and polite. 

Cheers, 

Clara

It sounds more like a question than a demand.  I would just respond saying its not feasible “due to timing of relocation”.