This is basically "copy or retype all the stuff from one card, and delete it", which is time-consuming. It would be so much better if a merge could be done, similar to what is done when comparing my tree and another tree - clicking on the "merge" button allows data to be copied from the other tree. In the case of duplicates, it would be great if there was a way to copy everything from one card (to be selected by the user) into the other card (also selected) using a similar merge page before deleting the duplicate card.
It's actually not copy and pasting; you simply can delete one of the duplicates and use the attach/detach feature of the FTB or site to connect the correct duplicate to the rest of the tree, if necessary.
Please, take a look on the comprehensive explanation of this functionality on the link below:
But what if you have some information (e.g. addresses, occupation, etc) in card #1 but not card #2, and have some information (e.g. place of death and education) in card #2 but not in card #1? The only way to get a full set on one card is to cut-and-paste, or retype.