Hi,
You can create a translation profile and define it under the voice-port or on the incoming dial-peer. For example if you want to translate 14401234567to 4000 for an incoming call from PSTN you can configure the below rule:
Voice translation-rule 1
rule 1 /14401234567/ /4000/
Voice translation-profile Incoming
translate called 1
Specify it under dial-peer or Voice-port and make sure you specify the correct direction as well. For example specify incoming if its for an incoming call.
dial-peer voice 1 pots
port 0/0/0:23
translation-profile incoming incoming
You can go through the link below to understand more about translation rules:
http://www.cisco.com/c/en/us/support/docs/voice/call-routing-dial-plans/61083-voice-transla-rules.html
Aseem