Hi,

You can use the Wait shape to pause a process in the life cycle of a case. By defining the conditions that cause a process to wait, you can create dependencies among cases in your application.

1. Add the Wait shape to the life cycle of your case.On the Workflow tab, click Life cycle.Hover over a process in a stage, and then click + Step > More > Utilities > Wait.Define the conditions that must be met before the process can resume.

2. To wait until a dynamic date or time is reached:

   1. In the Wait type list, select Timer.

   2. Click Reference date/time.

   3. Define a date in one of the following ways:

      • In the Date/Time field, press the Down Arrow key, and select the name of a property that stores a date and time.

      • Click the Gear icon next to the Date/Time field, and create an expression that returns a date and time value.

   Please refer 

   https://community.pega.com/sites/default/files/help_v731/procomhelpmain.htm#case-management/process-modeler/cm-configuring-wait-shape-tsk.htm​​​