Meaning trap
work on
to try to influence or persuade someone gradually
to attempt to change someone's opinion, attitude, or behaviour over time, often through subtle or persistent effort.

Don't mix these meanings
Same phrase, different job.
to attempt to change someone's opinion, attitude, or behaviour over time, often through subtle or persistent effort.
'work on' also has the more basic meaning 'to spend time improving or trying to achieve something'; this is the advanced sense.
Hear it in context
Notice where the phrase sounds natural.
She’s been working on her boss for weeks to get approval for the new project.
Some students argue that teachers should work on parents as well as pupils to create a more supportive learning environment.
Fix the pattern
One small grammar move makes it sound right.
Not: I'm still working my dad to let me go.
Say: I'm still working on my dad to let me go.
'Work ON' a person (persuade) — don't drop 'on'.
Which sounds natural?
Tap the one a native speaker would say.
'Work on someone' is the idiomatic way to say you're slowly bringing them round; the formal version is wordy.
Build natural chunks
Words that usually travel with it.
work on + person
- on my dad
- on her
- on the boss
- still
Don't confuse it
Related
Other meanings and phrases to compare.
- work on (to spend time improving or trying to achieve something) — 'work on' also has the more basic meaning 'to spend time improving or trying to achieve something'; this is the advanced sense.