If you are referring to Upromise REWARDS for making purchases from participating companies, you can request a check at anytime (there are some minimum and/or maximum amounts for any one withdrawal) and use the money for any purpose you choose - these REWARDS are considered rebates. If you otherwise QUALIFY to contribute to an IRA (i.e. earned wages, etc), you can use this money for that purpose.
If you are referring to the Upromise College Fund 529 Plan, I would think the withdrawal would have to be used for QHEE. Otherwise, it would be considered a non-qualified withdrawal and tax implications would apply.
The REWARDS program is separate from the Upromise COLLEGE FUND 529.
Hope this info helps.