Not at this moment. Some said such feature could be implemented later.
You can double spend it, but there is no easy way to "add" a fee to an existing transaction.
For a high-priority transaction, you can send it without any fee, and the wallet will not complain about it.
It will take more time (maybe a hour or so), but it will get included in a block eventually.
How do i double spend it, isn't that a bad thing? and what is a high pri transaction?
sorry for the noob questions