Volunteers who lobby infrequently at the Georgia Statehouse would be exempt from a proposal to tighten lobbying rules under a changed plan Thursday from a leading Republican. House Speaker David Ralston, R-Blue Ridge, said he revised his proposal to make clear that people who volunteer as lobbyists for no more than five days a year will not have to pay a registration fee or report their spending. His changed bill explicitly states that people expressing personal views to public officials are not lobbyists, eliminating earlier language that raised questions.