Thread Resurrection!

I want to give 1 month, but then I have quite a bit of unused leave so I want it to "offset" so I will leave in like 3 weeks instead ...

i.e. today is 2 May, if I put letter now by right I should only leave on 2 June right? But with some leave offsetting it should be few days earlier ... so what date should I put on my letter? 2nd June? I have no idea exactly how many days I have left due to pro-rating/etc ...