The MAS was originally named alongside The Pensions Advisory Service to carry out the Government's pledge of free, impartial help for retirees.
However, that decision was criticised in some quarters, with its performance already under scrutiny, in particular from the Treasury Committee.
Andrew Tyrie MP, chairman of the Treasury Committee, has been an outspoken critic of the MAS.
He said: "The Treasury Committee expressed serious reservations about the Government's initial proposals for providing this guidance. The new proposal addresses many of these concerns and is a big step in the right direction."

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Despite being dropped as one of the two main partners MAS said, however, it would help the Treasury with set up of the online function of the service and insisted it was still at "the heart of the delivery team" developing the new guidance service.
Caroline Rookes, chief executive of the MAS, said: "Our experts are seconded into HM Treasury, playing a key role in helping to build the online part of the service and develop the guidance which will be provided to customers.
"The Treasury have made it clear how much they value the contribution we are making. We are developing more extensive help for people aged 55 and over, to supplement the support they will get from the new guidance service.
"This will include help on budgeting for retirement, guidance on the different options and products available and a new annuities comparison table.
"We're also developing a new directory to make it easier for people to find a regulated adviser, if they need one."
The CAB will provide face to face guidance, and telephone guidance will be provided by TPAS.
Gillian Guy, chief executive of CAB, said: "The right guidance can be the key to a financially stable retirement.
"People who have diligently saved year after year towards their retirement deserve to choose how to make the most of their pension pot and good guidance is central to helping people make the right decisions for them.
"As a trusted, independent charity, Citizens Advice is in a unique position to deliver face to face pensions guidance. We have 75 years' experience working at the heart of communities, helping people get to grips with their finances. It's a natural fit for us to help people understand their pension options and make choices for their future."
Michelle Cracknell, chief executive of The Pensions Advisory Service, said: "Once we talk to people about their lives and their priorities, our experience is that we can get people to feel more confident about what they need to do next.
"CAB has a strong local and national presence and the partnership between TPAS and CAB has existed for many decades, so anyone who had a pension question had access to high quality free, impartial guidance on this topic.
"Our experience on the helpline is that our customers value the access to specialists and the bespoke and personalised conversations that we have with them about their retirement options."
Chancellor George Osborne said: "These organisations have years of experience dealing with a variety of consumer issues and are well placed to be accessible to everyone who reaches pension age and feels they would benefit from the guidance."