Reserved funds (not to be confused with "reserved" funds on the exchange) are funds that were acquired by the bot earlier but are not yet sold. These funds are "reserved" for this specific trade pair (market) with the intention to sell them there. This is even so when the market is currently not selected hence they would also not be used as a base currency on another market (see below for an example).
These reserved funds can easily be "released": Via the menu, select "Orders" and then scroll down to "Accumulated Funds (order history)" and click "RELEASE FUNDS".
A list of the original buy orders will be shown. You can select one or more of them to match the total quantity you would like to release and then click "Confirm".
Note that the acquired funds themselves on the exchange will not be touched in this operation and will remain in your wallet there. If you want to get rid of those too, you will have to sell them manually.
Example
Consider the following example to clarify things further: suppose 0.1 ETH is acquired on Bittrex:ETH/BTC. Then that amount of ETH is "reserved" on Bittrex:ETH /BTC.
If you then select ADA/ETH, then that 0.1 ETH will not be used as quote currency on ADA/ETH, because it is still "reserved" for selling on ETH/BTC.
However, if you would "release" the 0.1 ETH, then it would immediately become available as quote currency for ADA/ETH.