Discrepancy between external / internal job time case on résumé

Hi.

TL;DR : My external job title is different with my internal job title. What to do? (Sales Manager vs. Sr. Business coordinator)

I work as a business development role in B2B in the manufacturing industry. On my business card, and on the email signature, HR gave me a Sales Manager title. And that's what I use externally.

However, on the paystub I'm recorded as Sr. Business Coordinator. And internally, I am called Specialist.

I am not sure if I can use Sales Manager title on my résumé. Any advice is greatly appreciated!

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