Endorsing a check over to someone else is necessary if you are unable to cash a check on your own. It is a simple process involving one or two phone calls and a trip to the bank.
Coordinate with someone who has agreed to have the check signed over. This person must have a bank in the area where you are trying to cash the check, be willing to go to the bank to complete the signing and have enough money in the bank to cover the check in case it bounces.
Get assurance from a bank that it can handle the transaction. Perhaps first call the bank to ensure you don't waste your time going to the bank, if it is unable to handle the transaction.
Complete the transaction at the bank. On the back of the check, sign your name on the line. Under your signature, print, "Pay to the order of" followed by the person's name. Next, have the other person sign underneath this printed line.