Please read the T&C which specifically says conversion to another card does NOT preserve the points which would expire in 30 days after the closure of "sponsor account" that is the card those points are associated with.
For those who never care to explore TYP website - log in your account, go to your account summary and click on the points expired in 90 days even it says 0 - and pick Show All - you would be surprised by how PRECISELY Citi has the TYPs listed under each card from which the points are coming from.
Citi has this ability from Day One when it first introduced TYP program.
There is no any way to get around it.
The only way I could think of to somehow preserve the "value" without immediately using them is to book a Fully Refundable airline ticket - if this can be done with the current program since it is operated by a much worse outfit than before - then when you have actual trips coming up, go to the airport to ticket the new trip against the existing fully refundable ticket and ask the agent to issue you a voucher - Not sure this can work because in general the refund would have to go back to the original form of payment. I know CO would not do it, AA occasionally would. Use this method at your own risk.