How to change the push_access_level of protected branches

I have the release* branches as protected with push_access_level as “0” i.e “No One”.
Now i want to update the push_access_level to 40 i.e, “Maintainers”

How do i do this with the help of an API call.
I went through the gitlab api and found the below api call which is allowing only to make branches as protected but not to update them.
protected_branches

Could someone provide me or guide through the correct api call that i need to use.