Blue Prism doesn't have any native support for this that I know of.
While I'm not sure how well this would work, you could try checking into the runas command. For example, ""runas /user:domain\name cmd.exe"" would launch a command prompt window as the domain\name account. It does prompt for a password, however, which would likely require Blue Prism to send keys to the command prompt window to key in the password.
I might add that this seems an odd way to do something. Are you sure there isn't a better way to accomplish whatever it is you're trying to do?