When you have reserved funding, you have allocated an amount matched at a specified rate to be used whenever a leveraged position is open or increased and requires funding.
If your reserved funding is not being used, it is due to the fact that there are currently no positions that require funding.
If you wish to change your current matched funding rate used on your leveraged long/short position in order to use a reserved funding rate, you have to remove the current rate.
How to manually manage your funding:
https://support.bitfinex.com/hc/en-us/articles/360034669073-How-to-manually-manage-your-funding-
Welcome to the Bitfinex Help Center

Can't you find what you are looking for?
If you are having any problems or you have any questions, please talk to one of our friendly support representatives.