I had to do this the other day. I wrote out Verse 1 in the desired key, then changed the entire song to the new key that I wanted for Verse 2. I selected the Verse 1 bars and pressed Ctrl+C to copy, then Ctrl+Z to Undo the transposition of Verse 1. I then pasted the chords below verse 1 which remained in the new key, and then pressed F5 on the first bar of verse to let BB know about the new key.