Age UK will not take legal action against local Age Concerns that want to keep their names, the organisation has pledged.
Helena Herklots, the services director at Age UK, told Third Sector that the charity formed by the national bodies of Age Concern and Help the Aged last year did not want to make life difficult for local organisations.
"We hope groups will come with us, but we need to recognise that individual charities will make their own decisions," she said.
Sixty-three of the 320 local Age Concerns have agreed so far to become brand partners with Age UK. But some, including Birmingham and Liverpool, are unhappy with the terms and want to keep their names. There were fears that this would lead to a legal battle.
Herklots said there had been "lively discussions" with local groups. But she predicted that at least 150 Age Concerns would become brand partners by the March deadline.
She said she expected at least 150 more would accept offers to become 'friends' of Age UK. Friends organisations would still be called Age Concern, providing they added "friend of Age UK" to their names.
Herklots said that the friends package was developed for small Age Concerns, many of which were run entirely by volunteers, that are worried about losing their names and thought the terms of the brand partnership agreement were too onerous.
Asked if she was concerned about the possibility of a split between Age UK and the likes of Birmingham and Liverpool, which are planning to form a separate trading alliance, Herklots said: "Clearly our intention isn't to compete. We want to make sure an older person, wherever they live, can get help and advice."
In the report Investing in the Age UK Partnership, which was published this month, Age UK revealed its first year income was £160m. The report said that in its final year Age Concern England raised £91.2, while Help the Aged generated £74.3m in the 11 months leading up to merger.
The new organisation, which is moving to former government buildings in London's Tavistock Square, employs 2,500 staff - 500 fewer than the previous two combined.