Wakefield head coach Richard Agar has quit the Super League strugglers on Monday and been replaced by his Australian assistant James Webster.
Agar stepped down in the wake of his club's 20-12 defeat to Super League relegation rivals Bradford on Sunday.
Agar, who was in charge of Hull for four seasons from 2008, took over in October 2011 and guided Wakefield to a play-off spot in his first campaign on the back of a club Super League record run of seven successive wins.
"I spoke with the board of directors a number of weeks ago outlining the reasons why I had decided to look for another job within the game at the end of the season and therefore requested a release from the remaining two years of my contract," explained Agar, who was coach of France at the 2013 World Cup.
"The club has recently faced some extremely difficult and uncertain times and hopefully will be in a position in the near future to provide stability and consolidate their position in the top flight and give James the resources he needs to be successful."
Webster, a 34-year-old Australian who worked alongside Agar at Hull as well as Wakefield, takes charge straight away and his first game will be against bottom club London Broncos on Friday week.
"I would like to thank Michael and the board for giving me the opportunity to coach Wakefield Trinity, a club steeped in tradition," said Webster, who played for Hull KR and Widnes.
"Everyone at the club knew this would be a difficult year with some hurdles to overcome but we've set some goals and if we are successful in reaching them then I believe the club will be in a much stronger position going forward."