Possible Clues:

• Vary the tone of pub spotted in report
• Change the ending of popular fellow's talks with second half cut
• Modify or pass on disease across line
• Change the tone of leader of Conservatives in struggle with Left
• Vary the pitch of, as the voice
• Change one's tone to pass on complaint about left
• Student swallowed poison to put an end to it
• Change (the voice) in tone
• Vary pitch
• Modulate the voice