ChangeMonitor() — Changes the monitoring filename of a channel
Changes the name of the recorded file created by
monitoring a channel with the Monitor() application. This application
has no effect if the channel is not monitored. The argument
filename_base is the new filename base to use
for monitoring the channel.
; start recording this channel with a basename of 'sample'
exten => 123,1,Monitor(sample)
; change the filename base to 'example'
exten => 123,2,ChangeMonitor(example)