Hi @sas_23 ,
This is achievable but the method will based upon of your need. If you want to hide the Yes selection from the dropdown, you can modify the Items of the dropdown:
IsBlank(LookUp('Leave Request Form', Employee.DisplayName = User().FullName && 'Are you applying for mandatory leave' = "Yes") && Year('Leave Date')= Year(Today()))),
Community Support Team _ Jeffer Ni
If this post helps, then please consider Accept it as the solution to help the other members find it.