Anyone got a BMC URS? Seatpost advice.

Anyone got one and can explain how to change the seatpost height? I’ve found the 2 holes but despite searching the internet back to front I can’t find anything on how to unfasten the clamp.

The BMC website have got a manual section with all the other bike seat post clamps but not the URS, and the design is different.

Thanks!

For the sake of completion in case anyone reads in the future the issue was the seat post was stuck with carbon grip paste. A light tap freed it up.