Insert a column next to the date column. Assuming the first date is in cell A5 then in cell B5 insert this formula

`=VALUE(CONCATENATE(LEFT(A5,4),"-",MID(A5,5,2),"-",MID(A5,7,2)," ",MID(A5,10,2),":",MID(A5,12,2),":",MID(A5,14,2)))`

You should end up with a number with several decimal places aligned right. Format the cell, right-click and select Format Cells, in the dialog box choose Time and find the format you want, OK. Copy and paste or drag cell down column B to fill other dates. Copy these new dates and paste special (CTRL+SHIFT+V) Date & Time over the top of them. You can then delete column A.

Warning. I don’t use American dates so I am only assuming Calc will recognise the concatenated number as a date, it does for UK and NZ. If not, you might have to re-arrange the order of the bits of the number. Cheers, Al