Couple questions


I have a couple questions. One is regarding payments.

Can I make a temporary "sale" for payments and then delete it shortly afterward. Then will the members still get the benefits?
Or can I make edits to a payment and will the old members still be grandfathered into the old settings or will they get changed and have the new settings?

EDIT: I found the manual upgrade button. Nevermind. Still have a question about the above though,
The second question is:
Can I make temporary user upgrades? For example if I want to do a free membership giveaway and I want to give away a user upgrade that lasts for example 1 month. Can I do that?


The cost of user upgrades can be changed at any time.
But can the time be extended? Then will the old members be grandfathered into the old time?

Lets say its normally 6 months, then I make a limited time offer for one year at the same price. Will the people that already bought it only have 6 months or will they be upgraded to 1 year?