All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
In principle, it is permissible to call someone while omitting few letters from his name if this does not sadden him and if this is not said as a way of dispraising him. The Prophet called Abu Hurayrah: “O Abu Hir”, and he told ‘Uthmaan: “Write down, O ‘Uthm”, and told ‘Aa’ishah: ‘Aa’ish”.
However, the name which is mentioned in the question should not be pronounced in that manner because it is in principle the name of the Prophet and it has some virtues which other names do not have. Uttering this name in the manner which is mentioned in the question sounds like the mewing of cats; therefore, one should not pronounce it in the manner which is stated in the question.
Allaah Knows best.