How to change the size of an input argument in a predefined function?

Hello, I want to Import my recorded Signal with a microphone Array and use this Syntax: x = sensorsig(pos,ns,ang,ncov,scov) where scov is my recorded Signal. The size of scov has to be 1 by M vector of positive numbers (M=number of microphones), while my Signal is 1800 by M Matrix. Is there any way to Change the size of scove in the function?

Regards