Can you change my BTC adress to 186eCe4K2pskDHxkFh1ozUZ26zRX2RJXF4 pls
Thanks

Why not send it from the previous address? This is usually not done since it indicates possibly stolen acct
Yes , can you sign a message from your old address ?
I don't think signing an address proves much here since it may have been complicity sold and the original owner might sign anyways. The funds should be sent to the old address.