y:
to substitute this match
n:
to skip this match
a:
to substitute this and all remaining matches
q:
to quit the command
l:
to substitute this match and quit (think of "last")
^E:
to scroll the screen up by holding the Ctrl key and pressing E
^Y:
to scroll the screen down by holding the Ctrl key and pressing Y
However, the last two choices are only available, if your Vim is a normal, big or huge built or the insert_expand feature was enabled at compile time.