Set tomcat webapps folder

I need to set tomcat webapps to another folder of linux.
How can I set this?
I see that
Container: Apache Tomcat/5.5
catalina.base: /var/lib/tomcat5.5
catalina.home: /usr/share/tomcat5.5
Application base: /var/lib/tomcat5.5/webapps
Configuration base: /var/lib/tomcat5.5/conf/Catalina/localhost
but how can I change this?

Alter the appBase attribute of the Host container in your server.conf as needed: