KNOW THAT IT is mustaḥabb for travellers to say what others say after the ṣalāh of Ṣubḥ, which we have already explained. It is mustaḥabb for them also to say that which we relate from the book of Ibn as-Sunnī: that Abū Barazah 
reported that when the Messenger of Allah 
performed the ṣalāh of Ṣubḥ—the narrator said that he only knew that he said “during a journey”—he raised his voice so that his Companions heard him say: “O Allah, reform for me my religion, which You have made the preservation of my affairs. O Allah, reform for me my worldly life, in which is my livelihood” thrice; “And reform for me my Hereafter, to which You have made my return” thrice; “O Allah, I seek protection in Your pleasure from Your wrath; O Allah, I seek protection in You” thrice; “None can withhold what You grant, and none can grant what You withhold. The might of the mighty does not avail them before You.” [1].
reported that when the Messenger of Allah performed the ṣalāh of Ṣubḥ—the narrator said that he only knew that he said “during a journey”—he raised his voice so that his Companions heard him say: “O Allah, reform for me my religion, which You have made the preservation of my affairs. O Allah, reform for me my worldly life, in which is my livelihood” thrice; “And reform for me my Hereafter, to which You have made my return” thrice; “O Allah, I seek protection in Your pleasure from Your wrath; O Allah, I seek protection in You” thrice; “None can withhold what You grant, and none can grant what You withhold. The might of the mighty does not avail them before You.” [1].
Allāhumma aṣliḥ lī dīni-lladhī ja‘altahu ‘iṣmata amrī, Allāhumma aṣliḥ lī dunyāya-llatī ja‘alta fīhā ma‘āshī (x3).
Allāhumma aṣliḥ lī ākhirati-llatī ja‘alta ilayhā marji‘ī (x3).
Allāhumma a‘ūdhu bi-riḍāka min sakhaṭik, Allāhumma a‘ūdhu bik (x3).
Lā māni‘a li-mā a‘ṭayt, wa lā mu‘ṭiya li-mā mana‘t, wa lā yanfa‘u dha-l-jaddi minka-l-jadd.
Allāhumma aṣliḥ lī ākhirati-llatī ja‘alta ilayhā marji‘ī (x3).
Allāhumma a‘ūdhu bi-riḍāka min sakhaṭik, Allāhumma a‘ūdhu bik (x3).
Lā māni‘a li-mā a‘ṭayt, wa lā mu‘ṭiya li-mā mana‘t, wa lā yanfa‘u dha-l-jaddi minka-l-jadd.
References
[1] Ibn as-Sunnī (516).