Starting Saturday, you should use the full 10-digit number to dial local calls within some area codes, including the 660 area code in Missouri, according to guidance from the state. Providers across the country have agreed on April 24 as a soft launch for the effort aimed at transitioning callers in preparation for the introduction of 988 as a nationwide 3-digit emergency number for the National Suicide Prevention Lifeline. That means that callers cannot make a local 7-digit call to a number beginning with the 988 prefix, which affects 83 area codes across 37 states. In Missouri, the affected area codes are 314, 417, 660 and 816. Everyone in those area codes will be required to dial the 10-digit number for local calls in order to be connected starting in October. Local calls made with 7 digits will still be connected as usual until October 24, but people in the affected area codes are asked to start getting into the new habit starting April 24th.