Depending on your Call requirements, as an Administrator; you can allow or restrict submitters to withdraw their submissions per submission phase basis. To do so, follow these steps:
1. Go to Calls, and locate the desired call
2. Click Template from the top bar
3. Next to the submission phase you would like to update, click Edit
4. On the Submission Settings section, scroll down to Allow Withdrawal
5. Check the radio button to Yes, allow, or No, do not allow
Note: when creating a Call, this option is set to Yes, allow by default.
6. Click Save in the right top corner.