Ability to edit rejected gear

Some time ago, I replaced parts on my bikes. After that, I forgot to remove the old parts from my equipment and enter the new parts. As it is, days go by....
Since I know when I bought the parts and installed them, I wanted to do that now. Setting the new parts to the date of installation is not a problem, but there is no way to edit the date of replacement. So the mileage of the old parts is incorrect. I know it's a little geeky, but I like to compare the mileage of tires, chains, chainrings, etc.
@STRAVA: Would it be possible to implement this functionality for discontinued models as well?