Thought to be mistimed and had the date changed (9)
I believe the answer is:
meditated
'thought' is the definition.
(meditating is a kind of thinking)
'mistimed and had the date changed' is the wordplay.
I cannot quite understand how this works, but
'had' could be 'ate' (e.g. I had an ice cream) and 'ate' is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
'date' could be 'd' (abbreviation e.g. dob - date of birth) and 'd' is present in the answer.
This explanation may well be incorrect...
'to be' acts as a link.
Can you help me to learn more?
(Other definitions for meditated that I've seen before include "pondered" , "Engaged in spiritual contemplation" , "thought" , "Engaged in religious contemplation" .)