On Digital, later ITV Digital, was an early attempt to bring digital TV to British viewers. It was advertised by Johnny Vegas and a cute little Deadpan Snarker sock puppet monkey sidekick as in this advert. It wasn't a resounding success and ITV Digital died a quite public death with a lot of recrimination and lawsuits and all that fun stuff. But the Vegas/Monkey team were so loved that they ended up becoming the mascots of a completely different product, namely PG Tips. How do you reintroduce a pair of endearing and loved characters? Like this, apparently.
A literal example: Restoration Hardware, an upscale home furnishing chain, went from white walls, brightly lit stores, and a retro-industrial-Thirties/Forties/Fifties aesthetic to dark gray walls, very dim lights, and items with a modern/rough-edged look at some point after 2008.
T-Mobile tried this in Spring of 2012. Their spokeswoman, the T-Mobile Girl, before seen with only white backgrounds and wearing pink sundresses, is now being advertised as bored with the "nice, safe" life she has. She searches for, and finds, a black full-bodied motorcycle jumpsuit (with pink accents) and rides into the night on a Yamaha-looking sport bike.
Captain Morgan rum usually portrays their Captain as a playful partygoer. Their new campaign has gone for giving him a more daring and adventurous personality; likely due to the popularity of Pirates of the Caribbean.
Life Alert is a serious product - it's meant for older and disabled people if they ever, say fall down and need help when no one is around - but the old commercials have been the product of giggles for years. "I've fallen and I can't get up" is catchy and memetic but in 2014 they decided to darken up their ads into pure Nightmare Fuel. Gone are the old ladies almost comically on the floor, now the mood is noticeably darker and you can feel the fear.
Nationwide Insurance (2015 Super Bowl) - Many audiences thought this advertisement was try to pull too hard on heart-strings. A kid talks about life insurance but ends by saying "because I am dead". The commercial ends with the motto Make Safe Happen. This disturbing commercial aimed to up the ante during the crucial advertising season, which ended up backfiring.