[rsynnott]

What's on your passport may not be canonical. In some countries (Ireland and the UK, for instance) your name is, for practical (and generally legal!) purposes, whatever you use day to day; it wouldn't be _that_ uncommon for someone to have name X on their passport but have been going by name Y for years, and in this case name Y would probably be considered their legal name in most contexts.

[stevekemp]

I'm in that situation now, my UK passport/birth-certificate name is not the one I'm known by.

After several years of getting queried on mismatching ID, now I've moved to another country, I'm going through the process to "rename myself" - and mostly that's a matter of saying "Here's the name I've used for a long time, please make it official".

After the renaming goes through I'll be updating everything to match which will no doubt be a pain. But once it's done I'll have a much easier life.

[TillE]

Just as a really common anglo example, my passport has my middle name, but I will not otherwise use that name unless it's explicitly requested. Even airlines are inconsistent about this, so for most purposes I'm just Firstname Lastname.

At one point I had cards from two different banks, one with my middle name and one without.