I created the workflow in sharepoint designer using Collect data from user option. The approver receives three automated mail.
1) Notification to approve - Task assigned email 2) After approval, task has been changed alert 3) Another task has been changed alert
Is there an option to suppress the last two task has been changed alert? I would like to send only the Task assigned mail to approver
The first "You've been assigned a task" email is a feature of the Task list template and can be changed in List Settings > Advance Settings > Send e-mail when ownership is assigned.
The second two emails are "Alert me" emails. (Not sure why you are getting two, I suspect you my have signed up with 2 different users accounts that could even have the same email address.)
To delete the Alert Me for the currently logged on user.
Actions > Alert Me > View my existing alerts on this site
Then select your alert and Delete.
By the way - this is not a programming related question (See FAQ top right) so you may get quicker answers by posting similar questions on sites such as superuser.com or www.sharepointoverflow.com