In accordance with embodiments, the phone numbers specified by Sender_Num field may be changed in transit of SMS message 500 to facilitate one number servicing of multiple telephony devices. For instance, for a subscriber that is to be provided with one number servicing, the subscriber may originate an SMS message from a mobile terminal assigned to the subscriber, and the sender number of the Sender_Num field 502 may be replaced with a land-line enterprise directory number of a land-line telephony device assigned to the user prior to delivery of the SMS message to the destination device. In this manner, the user receiving the SMS message is presented with the land-line phone number of the originator in the SMS message. In a similar manner, when an SMS message is directed towards a user that is provided with one number servicing, an enterprise directory number of a land-line telephone assigned to the user may be entered by an originating party as the destination number to which the SMS message is directed. The destination number comprising a land-line phone number may be changed in transit of the SMS message to a MSISDN number assigned to the destination user such that the SMS message is routed to the mobile terminal of the destination user. In this manner, a person originating an SMS message to a destination user that is provided with one number servicing need only be aware of the destination user's land-line enterprise directory number.