How to change the default command character in linux screen from cntr+a to cntr+t

How to change the default command character in linux screen from cntr+a to
cntr+t

I have been using screen in linux and in some systems I get the default
command character in cntr+t, but in others I get cntr+a. How can I change
the configuration in those with cntr+a to cntr+t?
Thanks in advance, Saul