Quesstion on upgrading plans

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We have two subscriptions, call them A and B, all with parent Top and all exclusive. They have different pricing. We want a user to be able to upgrade from A to B. That works fine, except if A is unexpired, the new subscription B begins on the date of the upgrade. We'd like it to begin when A expires. Is there any way to set this up?

TIA.

Upgrades are done immediately. The only way you could do that is to only allow upgrading if the previous plan is already expired or doesn't exist, which is done using upgrade conditions under the Workflows tab of your plan.

So for example Plan B wouldn't be available unless Plan A is not active. Another option is to use prorating to credit their remaining time of Plan A towards the purchase of Plan B.