KT Corp., South Korea's No. 2 mobile carrier, said Tuesday it will accept voluntary retirement from senior employees in an apparent bid to tighten its belt as it is dragged down by lackluster performances. The company said it reached an agreement with its labor union to allow employees who have worked 15 years or more at KT to retire, which would cover about 23,000 of the current 32,000 workers. Applications will be accepted from Thursday to April 24. This is the first such step since 2009 when the mobile carrier implemented a restructuring program. Around 6,000 workers left at the time. Those who retire will be compensated with extra pay and a chance to work at KT's affiliates for two years.