Changing DD middle name by deed poll

[rosielea]

Sorry if this isn't the correct topic to post under, wasn't sure where would be better!
When i chose DD1s names I hadn't a clue about the importance (to me) of choosing meaningful names that i loved, it was a surprise pregnancy and i just sort of plucked names out of the ether! Now I'm on to naming DC3 and i feel i would really like to change DD1s middle name to something with more significance to us.
I understand this would seem a bit odd generally, DD1 is 4, but she unfortunately is profoundly disabled and doesn't know her own middle name so she wouldn't be confused by this. It makes me sad to think she will always be remembered by a name that is not 'her'. /i love her first name which is just right for her and my DD2 and the new baby have family middle names.
I've very hormonal (pregnant) at the moment and thinking alot about names but does this seem reasonable? And how do you change a name by deed poll?x

just stop using the old middle name and start using the new one
no legalese needed

Agree with Talkin - just use whatever names you like, there is no need to do it by deed poll.

I have never used the surname that is printed on my birth certificate (my DM remarried and I used my step-father's name) - it has never, ever been an issue - even when marrying/divorcing and remarrying again myself .

My middle name isn't even on my birth certificate. I didn't even find this out until I was in my late teens and applying for a university place when I needed a copy of my birth certificate.

My parents christened me with a middle name, but it was never official. As far as I'm concerned, it's my middle name. Legal piece of paper or not.