Seance and sundial

[Theroguard]

How dud the combo work with them

[BlackJester]

How dud the combo work with them

It is talked about in Combo Corner > Sudden Sundial.

Briefly, it only works on your turn. When {Séance} brings a creature back that creature will start a onetime "Exile this token at the beginning of the end step."
When this gets put on the stack at the end of the turn, activate the {Sundial of the Infinite} and it'll be gone for good, never to trigger again.