combine/merge 2 rows together using duplicate colomn

hi
my 2 userforms send data to sheet3 where conditional formatting looks up duplicates,and combines them and sends to sheet4,which sort of works
but location and name on frmissued and location and name on frmret should be in seperate colomns so that i know where it was taken to and returned to also could be returned by different guy,at the minute when its combined there should be no empty spaces or it wont combine and frmret overides the data in location and name so it only tells me who brought it back, can this be done have seen loads of duplicate code but none seems to point to this
any ideas please
cheers colin