Declining an Extra Day Offered

[muchlovex]

I've just started a new job and they've offered me and extra day (this would start from Sept). I have a think about it and I have accepted.
I've now thought about it more and I want to change my mind but I don't know how to explain this to my new manager. I don't want to seem as though I am messing him about, but I think it's best that I don't take the extra day.
Any thoughts or advise on how I decline this.

[ummmm]

Just explain it to him. The sooner you do it the sooner he can get someone else to cover that day.

[muchlovex]

Do you think an email would look bad? I always feel really uncomfortable saying things like this face-to-face.

[ummmm]

Not really. I would do it face to face if I was you. It's never usually as bad as you imagine it will be.