i can't remember if he only said he would cut it or if he actually did it?

Good question. I looked up and found this:

https://www.bbc.com/news/world-us-canada-52289056

A decision on whether the US resumes funding will be made after the review, which Mr Trump said would last 60 to 90 days.

https://www.cnn.com/2020/04/15/politics/trump-who-funding-congress/index.html

The Trump administration is working behind the scenes to abandon a commitment of millions of dollars in funding for the World Health Organization, despite President Donald Trump's announcement on Tuesday that his administration was pausing funding while reviewing the group's handling of the coronavirus pandemic, CNN has learned.

The move to completely slash the current allocated funding and prevent additional funds from being sent to the organization will set up a fight with Congress as the country is already struggling to handle the coronavirus pandemic.

This sounds like he's stopping all funding immediately, and it's already happening. So it's gone beyond talk.

also, i am not sure what is that supposed to change.

The US is the single largest funder of the WHO, so it will destroy their budget. Which will certainly change how they operate.