Is there any way to modify the monitoring tab to show the alarms occrence and ceased time?

What monitoring tab are we talking about? Could you provide me with a screenshot that highlights the tab?

Unfortunately I can't send a capture here but I meant the alarms tab inside PRTG so if you want me to send it please send me your email

Just open a ticket with support@paessler.com (i.e. send a mail) and attach the image itself :) Are we talking about adding different columns to the alert view (down and downsince)?