Compare column B - If exists then update date, else copy to end

Hi all

I am looking for some help with a macro. I am looking to use the value in column B on sheet 1 to check if they exist on sheet 2 column B. If they do exist then copy the data from sheet 1 to sheet 2 in order to update the data. If the data does not exist then copy the data to the end of the data on sheet 2. I am trying to consolidate some reports so need to copy the data as is. So on finding a match only copy the data on the row, in the example columns A to D, not the full row as this would upset the data that will be on my proper data.

Many thanks for any help in advance

Jim