Possible Missed Approach: Not Established at Decision Point

If you reach decision altitude and do not have visual contact, you execute the published missed approach procedure. You do not need permission from ATC—the clearance to land already includes the assumption that you may not land. However, you must inform ATC immediately.

Not Established—Missed Approach

Zurich Tower · HB-CDA

PILOT: Zurich Tower, HB-CDA, not established, executing missed approach.
ATC HB-CDA, go-around APPROVED, climb to flight level three-zero-zero, direct to Zurich VOR.
PILOT: Climb to flight level three-zero-zero, direct to Zurich VOR, HB-CDA.

The phrase "not established" is the key. It signals to ATC that you do not have adequate visual reference and are executing the missed approach. ATC is now prepared to give you holding or alternative instructions.