Final answer:
The command Parade Rest can indeed be given when a formation is at the position of attention, so the statement is true.
Step-by-step explanation:
The command Parade Rest is commonly used in military drill and ceremonies and can be given when a formation is at the position of attention. This command is generally used to provide a stance of rest while maintaining a degree of formality when the formation is not dismissed.
Therefore, the statement is true; the Parade Rest command can be given when a formation is at the position of attention. It's important to remember that personnel must snap to the position of attention first if they are not already in this position before assuming Parade Rest.