Q: I've just taken a new position, which I have to say is my dream job. But I can't abide the assistant I've inherited. How can I go about getting rid of them?
A: Malcolm Gladwell's book Blink and love at first sight notwithstanding, immediate impressions aren't always reliable. Some of the most abiding and satisfactory relationships start off in a very wary way.
Indeed, one of the Five Great Movie Plots features the disastrous encounter of two totally incompatible individuals - who, 90 minutes later, end up sharing a Nobel Prize, collaborating on a hit musical and/or finding conjugal bliss in Seattle. So please make sure that you've given yourself enough time to rate this new assistant thoroughly.
However, on the assumption that you've done all that, the sooner you take action the better. And better for your new assistant, as well as you. Being asked to move on immediately by a new boss looks a lot less negative on a person's CV than being fired after six months or more. After the initial shock, it will also be less damaging to your assistant's confidence. I realise you may find them so obnoxious that you don't give a fig how they feel - but you still should.
So speak to both your line manager and your HR director immediately. Make it plain that this is a move you're not just idly contemplating but are determined to make: you've only just taken up this new position and if you're to do it well, it's essential you have a compatible assistant in whom you have full confidence.
After that, be meticulous in following the advice and procedures you're given. Then, entirely separately, you might think about talking to the person from whom you inherited this assistant. It's not essential, but you'll have to make a lot more people-judgments before you're done and you'll find it valuable to discover whether your own assessment was broadly similar to that of your predecessor - or wildly different.