When I was pregnant with our second child and we were thinking of baby names, I asked my husband why he had insisted on a quite unusual first name for our then 10 year old. Was it, perhaps, a family name?
'No', he said, 'and I don't really like it now.' Sheesh!
So we asked our son what he felt about his name and he said he'd always hated it and would far prefer his second name (my choice).
So we decided to change it.
We put cards with this new name all round the house; we informed the school and by the time his brother was born, we were all used to the 'new' name and that's the way its been ever since.
Only has paternal grandparents who lived a long way from us and were rarely able to visit, ever called him by his original name.
We were told, however, that if it ever came to signing a legal document, my elder boy would need to put his full, registered name. No problem.