19. No amendment to a pension plan may become effective before the date it is registered with Retraite Québec, except in the following cases:(1) where the object of the amendment is the participation of another employer in a pension plan, in which case the amendment becomes effective on the date determined pursuant to section 13;
(1.1) where the object of the amendment is the withdrawal of a bankrupt employer from the multi-employer pension plan, in which case the amendment becomes effective on the date of the bankruptcy or, in the case of a target benefit plan, not later than the end of the fiscal year in which the bankruptcy occurs;
(2) where the amendment is to become effective on a given date prior to its registration, in which case the amendment may, provided it is registered, become effective on that date.