leave absence issue

hi,
I was created absence information to assign our employees, when i go and raise create absence in SSHR web page the below warning was showing.i added 2 accrual plans to our employes.
Is system allow the 2 accrual plans to one employee, if no i can i delete the one accrual plan...
can any one suggest...


"This absence will decrease the employee's PTO net entitlement to less than zero for one or more of their accrual plans."


thanks