A significant mistake in project planning is to assume full availability of all the team members. The management has the right to rearrange the employee vacation schedule to meet the deadlines. in the absence of a team member the project should not suffer so the PM should discuss with team members the plan in advance to avoid the conflicts and confusion during period of absence. The absent team member should inform their backups about the deliverable deadlines, key contracts summary of work in progress, major responsibilities ,access to important files and documents. The employee on vacation should inform his team member about best way to contract when on vacation if needed. Remind the employee about replying the office emails and voicemail in case of absence .Pm should also have part time employee backup when help is needed. He can also offer the employee to work from home and holiday pay. Vacation schedule should not be a hidden document so the team member can plan vacation around their colleagues schedule.