The comma after "however" in the original sentence was indeed an error. The corrected version,
"Shrek was disappointed when the store ran out of string cheese; however, the manager promised him a free pack next week."
uses a semicolon correctly to combine two independent clauses and a comma correctly to separate the manager's action from the rest of the sentence.
Step-by-step explanation:
Within the narrative, the principal characters are propelled by specific goals and underlying motivations, infusing the story with depth and resonance. Examining the sentence's construction, the original inclusion of a comma after "however" was a grammatical misstep. The revised rendition, "Shrek was disheartened when the store ran out of string cheese; however, the manager promised him a free pack next week," adeptly rectifies this by employing a semicolon to elegantly conjoin two independent clauses. Simultaneously, the use of a comma serves to judiciously separate the manager's commitment from the rest of the sentence, ensuring syntactic accuracy. This correction not only aligns with grammatical conventions but also enhances the clarity and fluidity of the expression, enriching the storytelling experience.