Lee Gadd, 51, was found by police officers with multiple back and neck wounds in his home, in Broad Lane, Bloxwich, last year.
At Wolverhampton Crown Court last month Bradley Pye, 24, denied murdering Mr Gadd between May 22 and 25, 2021 – but pleaded guilty to his manslaughter.
However, his guilty plea to manslaughter was rejected by the Crown Prosecution Service(CPS) and a jury trial was set for September.
A hearing held in the defendant's absence in the court on Monday was told that the CPS has now decided that the guilty plea was "acceptable".
Pye, also of Broad Lane, who was remanded into custody, will be sentenced on June 10.
Mr Gadd served as a trooper with the Queen’s Royal Lancers before setting up his own plumbing business.
Following his death his family said he was a “dedicated father and family man”.
His body was found was on May 24 by West Midlands Police after his neighbours raised concerns for his welfare.
A family statement said: “No words can describe the pain we are suffering. We are a devastated family with the loss of our Lee, he was a dedicated father and family man.
“He was a funny, caring and loyal person, and a huge hole has been left in our family and our hearts.
“Our lives will never be the same again.”
Flowers and tributes were also left outside Mr Gadd’s home in Bloxwich. A tribute card read: “Lee, I cannot believe that you have been taken from us. We had so many more years to see each other grow old.”