Woodcliff Lake, N.J. — Party City Holdco Inc. has filed for Chapter 11 bankruptcy. The restructuring process is expected to substantially reduce the company’s debt and optimize its capital structure and liquidity. The company expects to complete the restructuring process in the second quarter of this year. Party City’s more than 800 stores will remain open during the bankruptcy process. The company says it will continue to advance its key initiatives underway, such as converting stores to next-generation prototypes, evolving Halloween City pop-up stores, building out its online shopping experience, …