The newly joined coordinator wants that she should be called by first name in contrast the persons who report to him call her as "Didi" as a mark of respect. However, "Didi" also does not go well in corporate culture since the word signifies family culture.
In the office we need to have professional relationship. Against this backdrop, you have two options. One is to allow the juniors to call her by the first name. Nevertheless, she need to be respected and by no way respected can be diluted. Allowing her to be called by first name has risk as juniors could misinterpret it as if she does not any seniority or authority.
The next option, which conservative company like yours may have is to call her as "____ Madam". The blank that I have left open could be either her first name or surname. This will bring sort of mental distance between the juniors and her. In conservative companies this distance is necessary. Convince the senior lady on importance of maintaining mental distance.
In MNCs even CEO or MD is called by first name. Nevertheless, staff is mature and they understand very well that calling by first name does not demean his/her position in any way. Does your organisation has that maturity? If not, then leapfrogging to modernity could pose a risk.
16th January 2017 From India, Bangalore
Here the main problem is about the mentality of the people, most of them think that person of same age can only be called by simply by the FIRST NAME. And they will not accept the 2nd option, as they have ego problem.
As mentioned by you, calling 'Didi" brings FAMILY CULTURE, which is really awkward.
We will try to use the 1st option. Let us try................
18th January 2017 From India, Guwahati