170. Procedure for discontinuing

(1) To discontinue all or part of a claim, a claimant must file a notice of discontinuance and serve a copy of that notice on every other party to the proceedings in accordance with Part 4 of these Rules.
(2) Discontinuance against any defendant takes effect on the date when the notice of discontinuance is served on him and, subject to paragraph (3), the proceedings are brought to an end as against him on that date.
(3) However, this does not affect proceedings to deal with any question of costs.