Complex sentence: At the time, I. Magnin Co. was located at Grant and Geary Streets, however in 1948 when I. Magnin built the new flagship store at Stockton and Geary streets, the two flagship stores were less than a block apart.
Split into simpler sentences: At the time, I. Magnin Co. was located at Grant and Geary Streets. However in 1948 when I. Magnin built the new flagship store at Stockton and Geary streets, the two flagship stores were less than a block apart.