It's better to tell the truth, most leaders will support it, because it takes a long time to prepare for the interview, not a day or two. If you lie, it is easy to be exposed and have a bad influence. If you don't get the opinion of the leader, the interview will be affected and the loss will outweigh the gain. Tell the leader sincerely that you cherish this opportunity and thank him if he agrees. In addition, even if you are admitted to a civil servant, you need the consent of the unit leader to transfer, so you should humbly ask for leave from the leader.