Dhaka, July 3 -- Thailand's acting prime minister is set to helm the country for only one full day Wednesday, standing in for suspended premier Paetongtarn Shinawatra before being replaced himself in a cabinet reshuffle.

Transport minister and deputy prime minister Suriya Jungrungreangkit began his engagements by attending a ceremony in Bangkok celebrating the longevity of the prime minister's office.

The event marks the 93rd anniversary of an institution Suriya is set to command for far fewer than 93 hours as Thailand reels from the suspension of Paetongtarn, heiress of the country's dominant political dynasty.

The Constitutional Court said Tuesday there was "sufficient cause to suspect" she breached ministerial ethics during a diplom...