It's easy to transfer your American Express Points to JetBlue. Contact American Express to find out the exchange rate to change Membership Rewards points to TrueBlue points. You also need to link your Membership Rewards account to your TrueBlue. This can be done over the phone.
Check the JetBlue website to see how many points are required for the flight, then use the "TrueBlue points" fare selector. Since the number of points can change at any time, you may want to transfer over extra points. The points must be transferred to the TrueBlue account before you can book the flight.
Limitations and Rules
There's no limit on the number of transfer points, but it's not a one-to-one ratio. Speak to a representative to find out how many points will need to be transferred. The TrueBlue number and your last name have to be an exact match with the information in TrueBlue's database. It may take up to 48 hours for the points to appear in your account.