Fixing errors of conversion

I have converted a PDF into an .mscz fairly successfully, with only a few errors. It looks like extra rests have been inserted (in grey) where the time value of the note was read incorrectly. The problem is I can't seem to select those grey rests to delete them, or fix the time values of the other notes in the bar. I would upload wither the PDF or the .mscz file, but can't seem to succeed at that using the "Choose a file" below.
Can you help?
Ron Skelton.