An article on this
https://www.theverge.com/22789561/nasa-jwst-james-webb-space-telescope-priorities-astronomy-astrophysics-exoplanets#:~:text=Roughly%2010%2C000%20hours%20of%20observing,build%20JWST%20and%20its%20instruments.
There is a process for urgent observations- for instance if LIGO detects a neutron star merger and locates it in the sky with high precision, JWST might be called upon to interrupt its scheduled observations and look for the optical afterglow...
As excited as we all are, I suspect we will all have our expectations surpassed by what JWST will show us...
I cannot wait to see what it reveals!