SINGAPORE (Reuters) - Southeast Asian ride-hailing firm Grab said on Thursday it is offering some staff unpaid leave and senior executives are taking salary cuts as it moves to conserve cash amid falling demand because of the novel coronavirus outbreak. "Senior Grab leaders are reducing salaries by up to 20% this year and we have given employees across the region, in teams where there is excess capacity - the option to take flexible working arrangements," Grab, the region's most valuable..