Roger that

In voice procedures
"Roger" means "GUM" (got your message) in both military- and civilian aviation radio communications. This usage comes from the initial R of received: R was called Roger in then-current radio alphabets such as the Joint Army/Navy Phonetic Alphabet. It is commonly followed by the word that to form "Roger That". It is also often shortened in writing to "rgr". R is Romeo in the modern NATO phonetic alphabet; the updated phrases now in use are
for example
"I'll Romeo that" or "Romeo and Out".