Question: If a person starts a journey when it is quite close to the end of the time for a fard salat or if one becomes a muqim (resident) when it is quite close to the end of the time for a fard salat, how many rak'ats should one offer if one has not performed it yet?
ANSWER
If one starts a journey when it is quite close to the end of the time for a four-rak'at fard salat, one must perform it as two rak'ats if one has not performed it yet. If one becomes a muqim when it is quite close to the end of the time for a four-rak'at fard salat, one must perform it as four rak'ats if one has not performed it yet.

A traveler, on his/her way back, remains a traveler until he/she reaches the place where he/she became a traveler in the beginning. He/she becomes a muqim as soon as he/she arrives there.