Expressions for thanking

• Thank you for your help. / time / assistance / support.
• I really appreciate the help. / time / assistance / support you’ve given me.
• Thank you once more for your help in this matter.

Expressions with a future focus

• I look forward to hearing from you soon / meeting you next Tuesday.
• I look forward to seeing you soon.
• I'm looking forward to your reply.
• We hope that we may continue to rely on your valued custom.
• We look forward to a successful working relationship in the future.
• Please advise as necessary.
• I would appreciate your immediate attention to this matter.

Expressions for showing them you want to help

• If I can be of assistance, please do not hesitate to contact me.
• If you require any further information, feel free to contact me.
• If you require any further information, let me know.
• Please feel free to contact me if you need any further information.
• Please let me know if you have any questions.
• I hope the above is useful to you.
• Should you need any further information, please do not hesitate to contact me.
• Please contact me if there are any problems.
• Let me know if you need anything else.
• Drop me a line if I can do anything else for you.