Dim InputDT As New DataTable
InputDT.Columns.Add(New DataColumn("test"))
dt.Columns("test").DataType = GetType(Date)

Dim InputDT As New DataTable
InputDT.Columns.Add(New DataColumn("test"))
InputDT.Rows.Add("1/1/2018")

Dim clonedDT As DataTable = InputDT.Clone()
clonedDT.Columns("test").DataType = GetType(Date)
For Each row As DataRow In InputDT.Rows
    clonedDT.ImportRow(row)
Next