Yes, you can – and vice versa.
You can transfer your money to a cash ISA from a stocks & shares ISA and back again as many times as you like, giving you more flexibility in managing your tax-free savings. This is also the case for innovative finance ISAs, providing it allows you access to your cash – the higher rates are for longer fixed terms.
Check that your intended provider accepts transfers – some don't. And also watch out for fees on stocks & shares ISAs and innovative finance ISAs. You may be charged to set up the ISA or to leave it, so multiple transfers may lose you money.