"assist if needed" is correct and usable in written English.
You can use it to offer help to someone. For example, "Let me know if you need any assistance with the project, and I'll be happy to assist if needed."
He was asked to assist, if needed, in the delivery room.
New Brunswick Power indicated that repair crews were on standby and neighbouring utilities have been called to assist if needed.
I had time on my hands to prepare, no public distraction or interference, and my colleagues from Alaska Department of Fish & Game were on hand to monitor and assist if needed.
The best way to treat placenta accreta is to diagnose it early, through ultrasound or MRI, so that an OB/GYN can plan for the birth by making sure there's a sufficient supply of blood available, as well as bring in surgeons and other specialists to assist if needed.
A project coordinator could assist if needed.
The questionnaire was completed during class hours with a researcher from the research group present, ready to assist if needed.
Study investigators, who were doctors familiar with IBS and the EQ-5D, were available to answer questions and assist respondents (if needed ) in the completion of the questionnaire (provided in English and Chinese).
Ask the bookstore employees to assist you if needed.
There are qualified art therapists who can assist you if needed.
If you set your maximum bid, secured financing and hired professionals to assist you if needed, you should close on a Fannie or Freddie foreclosure.
Take this into consideration when arranging your mirror near natural light; a heavy curtain might assist if you need to place it across a window space.
