Well,the first thing I will do if am entrusted with something that is not my field and am not really an expert in is to study about it,do an intensive research about what has been entrusted to me.
I will also consult people who are experts in such areas ask them to put me through,tutor me how to go about it.
You know nobody is an island of knowledge so you can be an expert in every area but you might find your self working in such field.
And also you can take a professional course in that field and learn more on how to handle such responsibility.
You are truly a reliable and responsible worker, hard work and strong determination to succeed