You cannot Constitutionally impeach a civilian.
I'm, of course< referring to this next impeachment trial proposed by the drunk and her bitches.
No, you are asking if the Senate can TRY an impeachment which was passed when the impeached person was in office, as is the case here.
Article I ยง4 says, “The Senate SHALL have the power to try ALL impeachments”, and, never mind the House of Commons in 1558, the US Senate has tried and convicted persons impeached while in office who were out of office when tried.