Thanks Dave. I was able to make it work--sort of. I isolated the wrong dated QSOs and did set up the exchange for the dates but ended up zeroing out the start and end times in minutes and seconds. Apparently, I could not simply insert the date only as a replacement without adding a further instruction to ignore the time info but I don't know or see how to do that. In this case, it isn't that vital for my purposes.
+ Hopefully you made the backup copy of your log, as suggested in my previous post. Make a copy of the backup, and then restore the backup as your log. Then
1. Filter the Log Page Display to contain the QSOs with the incorrect date
2. in the "Modify QSOs" panel
2a. set the "Item Name" selector to "QSO_Begin"
2b. set the "Item new value" to +24h
2c. click the Mod button
2d. set the "Item Name" selector to "QSO_End"
2e. set the "Item new value" to +24h
2f. click the Mod button