LONDON — Thomson Financial  reported that API Group PLC Chief Executive David Walton has resigned, but will remain as CEO with the company for the time being. Walton’s move comes as the company said it expects its first half results to be broadly in line with expectations, and to represent an improvement over last year’s first quarter. The optimistic forecast, however, relies on significant initiatives within the laminates business, uncertain dollar exchange rate movements and recent changes in VAT regulations in China.