since it is a financial instrument with value
you certainly should be able to.
The obvious people to ask are the people who give loans.
even if they give tinkly laughs and say: 'oh we dont do THAT sort of thing hahah titter titter'
[ as a bank did when I asked for a buy-to-let loan ]
I am not sure if it wold be that cheap - altho better than an unsecured loan.
You are of course quite RIGHT not to go for the other options - known as the Ugly sisters or Ugly Twins - stop paying (making it paid up) and selling it back to the endowment company (rip off yet again yawn) or selling it on the open market
and good luck
I did the same as you and hung onto the policy as a savings vehicle -nice to have the pot of well silver at the end, but if you do the sums, the last ten years has been pretty crap