To sign over a check to an individual, other than the original recipient, the original payee should write 'pay to the order of' on the back of the check. Then the payee should list the individual receiving the check followed by the signature of the original recipient.
The individual receiving the signed over check could have difficulties cashing it. This depends on the policies of the bank used to cash it. To avoid potential difficulties, the check could be cashed by the original individual and the funds could then be transferred into the account of the second individual. This is more time consuming but will not present problems at the bank.