Polite Requests and Formal Situations

Could you please help?

A polite request for someone to assist you

I would be grateful if

A formal phrase to make a polite request

May I ask you something?

A polite question asking permission before raising a topic

Excuse me for interrupting

A polite apology before speaking while someone else is talking

I am sorry to bother you

A phrase to apologise for taking up someone's time

Would it be possible?

A polite question asking if something can be arranged

Thank you for your time

A phrase to express gratitude for someone's attention

I appreciate your help

A phrase to say you are grateful for assistance received

Please let me know

A phrase asking someone to inform you when something happens

At your convenience

A phrase meaning whenever suits you best

I look forward to your reply

A formal phrase expressing anticipation of a response

With respect

A formal phrase used before politely disagreeing