Mo. Rev. Stat. § 516.320: Actions barred, only revived by written promise.

In actions founded on any contract, no acknowledgment or promise hereafter made shall be evidence of a new or continuing contract, whereby to take any case out of the operation of the provisions of sections 516.100 to 516.370, or deprive any party of the benefit thereof, unless such acknowledgment or promise be made or contained by or in some writing subscribed by the party chargeable thereby.