8/15/19 AIM  En Route Procedures 5 − 3 − 4 NOTE − ICAO Document 10037, Global Operational Data Link (GOLD) Manual does not include this in its tables. CPDLC Message Sets Operational Definition in PANS − ATM (Doc 4444) FANS 1/A ATN B1 Response Message  Element  Identifier Message Element Intended Use Format for  Message Element Display UM23 DESCEND TO AND MAINTAIN  (altitude) Note  −  Used for a sin- gle level UM23 DESCEND TO ( level ) W/U LVLU − 9 Instruction that a descent to the specified level or vertical range is to commence and once reached is to be maintained. DESCEND TO ( level ) UM36 EXPEDITE CLIMB TO (altitude) Note  −  This message element is equivalent to SUPU − 3 plus LVLU − 6 in Doc 4444. N/A W/U LVLU − 6 Instruction that a climb to the speci- fied level or verti- cal range is to commence and once reached is to be maintained. CLIMB TO ( level ) UM37 EXPEDITE DESCEND TO  (altitude) N/A W/U LVLU − 9 Instruction that a descent to the specified level or vertical range is to commence and once reached is to be maintained. DESCEND TO ( level ) UM38 IMMEDIATE- LY CLIMB TO (altitude) Note  −  This message element is equivalent to EMGU − 2 plus LVLU − 6 in Doc 4444. N/A W/U LVLU − 6 Instruction that a climb to the speci- fied level or verti- cal range is to commence and once reached is to be maintained. CLIMB TO ( level ) UM39 IMMEDIATE- LY DESCEND TO  (altitude) Note  −  This message element is equivalent to EMGU − 2 plus LVLU − 9 in Doc 4444. N/A W/U LVLU − 9 Instruction that a descent to the specified level or vertical range is to commence and once reached is to be maintained. DESCEND TO ( level ) UM135 CONFIRM ASSIGNED ALTI- TUDE Note  −  NE response attribute N/A Y LVLU − 27 Request to confirm the assigned level. CONFIRM AS- SIGNED LEVEL UM177 AT PILOTS DISCRETION N/A NE See Note Request to confirm the assigned level.