Can I use coccinelle to change argument types in a function signature

I am new to coccinelle and trying to find how can I change argument types in function signatures.

I have a function that takes a pointer of type T1 as an argument

int fn(T1* p)

I would like to change the function to take an argument of type T2 as follows

int fn(T2* p)

Can someone point me to an example that changes argument type . I am able to find examples to changer order and number of args.

Thanks in advance.