By Richard Warry
BBC News website health editor
For most people a switch to regular day shifts after a career of working anti-social hours would be great news.
Dave was diagnosed with liver cirrhosis
For policeman Dave Corefield it almost spelled disaster.
Dave, 55, from Salford, Manchester, had been in tip top shape, working out three times a week in the gym.
But after 25 years of burning the midnight oil he decided to make the most of finally getting regular evenings off.
Soon he was downing up to ten pints a night.
Drinking wasn't his only hobby - he also took up amateur dramatics.
But a fall from a stage left him practically immobile - and just encouraged him to drink even more.
His weight soared to 22 stone, and he noticed yellow patches in the corner of his eyes. It was a classic sign of jaundice, but Dave refused to admit to himself that anything could be wrong.
He knew he had to take action when people commented on his appearance at his mother's funeral.
"Friends came up to me and said: 'what is the matter with you, you are so yellow?'", he said.
Dave finally went to see his GP in November 2002. He was immediately referred to his local hospital, where he was diagnosed with cirrhosis of the liver.
"I must have had an idea that I had been drinking too much, but I didn't realise it had been as bad as it was," he said.
"It really shocked me."
Initially, doctors tried to treat Dave with drugs, but his condition was too advanced.
Each month for the next six months he was stricken with a condition called hepatitic encephalopathy - caused by poisons that his damaged liver was unable to break down attacking cells in his brain.
Dave knew deep down he was drinking too much
"I couldn't think, or rationalise, and once I came round after apparently being in hospital for 24 hours," he said.
"They asked me what year it was, and I said 1971."
By September 2003, doctors said there was no more they could do for Dave: they told him his only option was a liver transplant.
He was referred for assessment at St James' Hospital in Leeds.
"I knew I had to convince them that I was a worthwhile candidate for a transplant," he said.
"I knew that if I did not get one, then I was going to die."
It helped that Dave had stopped drinking overnight when first diagnosed with cirrhosis.
He had also lost seven stone, in part due to the fact that his body was unable to process protein in the diet, and so had started feeding off that found in the muscles.
Doctors at St James' put him on the waiting list for a transplant, and an organ came up in April 2004.
Illness took its toll
"I had three feelings when I heard the news: 'thank goodness for that', 'oh dear, someone has died', and then, 'am I going to make it?'
"I was so lucky to get it when I did. The longer I had left it, the less chance I would have had of making a full recovery."
Now Dave is back behind his desk, lending administrative support to police investigations.
He knows how close he came to death, and is determined to make the most of a second chance.
"I feel I am the luckiest guy in the world," he said.
"I don't need alcohol any more. I know too well what it can do to people."