Duaa-When leaving the residence of the host.

When leaving the residence of the host
Recite:
اللَّهُمَّ بَارِكْ لَهُمْ فِيمَا رَزَقْتَهُمْ وَاغْفِرْ لَهُمْ وَارْحَمْهُمْ
"O Allah, grant him Your blessings in his sustenance, forgive him and have mercy on him".

(Mishkat)