Reference to a non-shared member requires an object reference occurs when calling public sub

You either have to make the method Shared or use an instance of the class General:

Dim gen = New General()
gen.updateDynamics(get_prospect.dynamicsID)

or

General.updateDynamics(get_prospect.dynamicsID)

Public Shared Sub updateDynamics(dynID As Int32)
    ' ... '
End Sub

Shared(VB.NET)