Stephen Kenny has replaced Mick McCarthy as Republic of Ireland manager with immediate effect.
McCarthy's contract was due to run until July 31, after the Euro 2020 finals were originally due to finish, with Kenny set to step up from his role with the U21s on August 1.
The Republic are due to face Slovakia away in the Euro 2020 qualifying play-offs, with the winner to face either Northern Ireland or Bosnia and Herzegovina, but the fixture has been postponed for a second time due to the pandemic.
Speaking on FAI TV, McCarthy said: "It's disappointing I can't finish it off. I think we've had a really good campaign and we were almost there in November when we played Denmark.
"So the play-offs have been pushed back and I fully understand it. Stephen has been contracted to take over in August and good luck to him. He'll get the chance now to qualify.
"It's been brilliant. I've loved being back, I've thoroughly enjoyed it. It's been an absolute honour and a privilege to do the job again and I think I'm leaving Stephen with a healthy balance to be honest."
McCarthy added: "I support the decision and I'm absolutely staying in football."
Interim FAI CEO, Gary Owens, said: "This has been a difficult situation for the Association - and for Mick and Stephen in particular - in the wake of the Covid-19 pandemic and the effect it has had on the football calendar.
"On behalf of the FAI, I wish to express our gratitude to Mick for his service and commitment to our national team throughout his career and particularly in his second spell as Ireland manager. We wish Mick and his staff well and we thank them all for their hard work in this European Championship campaign to date.
"Stephen will now begin his planning for the play-off against Slovakia and everyone at the FAI wishes him well in our bid to qualify for Euro 2020. Football will be back and we have so much to look forward to now in the autumn with the Nations League and the UEFA EURO 2020 play-off, followed by the World Cup qualifiers in early 2021."
The match against Slovakia was originally due to take place on March 26, but was shifted to the June international window due to the suspension of football across Europe.
UEFA announced earlier this week that no international football would go ahead in June, with no new dates announced.