(Updates prices, adds comments; changes byline, dateline, pvs LONDON)
* ECB's Draghi says to discuss possible changes to bond-buying
* Euro on course for biggest one-day pct gain in more than 3 weeks
* Graphic: World FX rates in 2017 tmsnrt.rs/2egbfVh
By Sam Forgione
NEW YORK, July 20 (Reuters) - The dollar fell to its lowest in nearly two years against the euro on Thursday after European Central Bank chief Mario Draghi said policymakers would discuss possible changes to its bond-buying scheme in the autumn.
Though Draghi said no date had been set for discussing any changes to the program and that ECB rate-setters had been unanimous in their decision not to change their guidance on monetary policy, investors suspected discussions in the autumn would lead to monetary tightening next year.
The euro climbed as high as $1.1655 against the greenback after Draghi spoke, putting it up about 1.2 percent on the day and marking its highest level since August 2015. The euro was last on course for its biggest daily percentage gain in more than three weeks.
The dollar index, which measures the greenback against a basket of six major rivals, hit a session low of 94.090, marking its lowest level in nearly a year.
"The marketplace is looking for a good potential for (quantitative easing) reduction to start in September or at least to be announced in September," said Richard Scalone, co-head of foreign exchange at TJM Brokerage in Chicago.
Analysts said the dollar also remained weaker given the collapse late on Monday of a Republican overhaul of the U.S. healthcare system. Weak economic data has also lowered expectations for another interest rate increase from the Federal Reserve later this year.
"The dollar is now suffering and lagging due to the (Trump) administration's inability to push through any kind of reforms," said Jason Leinwand, founder of FirstLine FX Currency Strategy in Randolph, New Jersey.
The dollar fell about 0.3 percent against the yen to a session low of 111.63 yen. That remained just slightly above Wednesday's more than three-week low against the Japanese currency of 111.53 yen.
The Bank of Japan kept monetary policy steady on Thursday but once again pushed back the timing for achieving its ambitious inflation target. The view that the BoJ was maintaining its easy money policies allowed the dollar to remain somewhat firmer against the yen, analysts said.
"There is not going to be any shift in policy from the Bank of Japan," Leinwand said. (Reporting by Sam Forgione; additional reporting by Saikat Chatterjee in London; Editing by Meredith Mazzilli)