Originally Posted by WineCountryUA

This is an area were things are rapidly changing. In the past the dual use was not allow and travel bank was only for all UA itins.

Now you say for an all UA you can use together. That is an example of some of the recent changes. ETCs can not be used for partners, which is new.

Expect more changes to come. UA is making these flight credits easier to use and easier to to use multiple together. But it is still a Work in Progress -- Issues using FFCs or ETCs (travel credits) for payment

You can convert the travel bank funds to an FFC if you find any set of flights for the right amount (wait at least > 24 hours). Wait a few days and cancel --- viola, an FFC which can now be used with another FFC.