Masking the line behind a different CIDc

Hello colleagues, I wanted to mask the director’s line (FreePBX 13) 277278305 as the assistant’s line 277278300, but it does not work. I have a SIP trunk 2772783xx, I edited the CID, deleted the CalerID in out. route…
For calls inside FreePBX ok, for calls outside FreePBX no.
Does anyone have an idea? Thank you Peter