Help with referencing a list

[bakerjase]

I have two columns with a date in each cell. Each couple of dates references a particular worksheet, the worksheet number corresponds with the row number of the dates. How can I make a macro that will use the worksheet number to look up those dates?

There are two dates because one will need to be searched for and the other will replace it.

Sorry if that's a bit muddled, my brain is a little fried