From the help text that it's "spitting" out:
ModifyServer(ms) {name|id} [attr1 value1 [attr2 value2...]]
ModifyConfig(mcf) attr1 value1 [attr2 value2...]
So, ms takes the server name as it's first arg, then a list of key value pairs.
mcf, on the other hand, takes no server name argument.
soooo
zmprov ms SERVER zimbraMailPort 88
zmprov gs SERVER | grep zimbraMailPort
tomcat stop
tomcat start |