Denny is charged with second-degree murder in the death of 49-year-old Raymond Taavel on April 17, 2012 outside Menz Bar, a popular gay club on Gottingen Street.
His eight-week trial was scheduled to begin Tuesday, but that is now postponed.
On Tuesday morning Denny announced he wanted to fire lawyer Don Murray. Murray then asked to withdraw.
Denny told the court Murray is no longer "trustworthy" and he can get a lawyer in 10 days.
"Unfortunately he's very angry at me and I am very angry with him," he said referring to Murray.
Justice Peter Rosinski says Denny was found fit to stand trial so he's allowed to make decisions about his own case, even if they're not in his best interest.
A new lawyer will have to be approved by Legal Aid and capable of handling a murder trial.
The case has been put over until Sept. 25.
This is the second time Denny has tried to fire his lawyer. He rehired Murray after his preliminary hearing in March 2013.
Denny was at large from the East Coast Forensic Hospital when Taavel was killed. Denny had failed to return to the hospital after being granted a one-hour leave April 2012 — an incident that led government officials to review release protocols for psychiatric patients.