By Nicole Gaouette, Jennifer Hansler and Kylie Atwood, CNN

(CNN) -- President Joe Biden is set to announce a series of significant changes to US foreign policy including measures on Yemen and LBGTQ rights during a speech at the State Department, National Security Adviser Jake Sullivan said Thursday.

Biden will announce an end to all American support for offensive operations in Yemen in his remarks, Sullivan said, and will appoint an envoy to focus on the long-standing conflict. The President "will talk about the United States playing a more active and engaged role" in ending the war, Sullivan said.

Biden will also announce a presidential memorandum on protecting the rights of LGBTQ individuals worldwide, a reflection of his "deep commitment to these issues, both here in the United States and everywhere around the world," Sullivan told reporters in the briefing room.

The President, who is set to visit the State Department later Thursday with Vice President Kamala Harris, will use the speech not only to unveil policy changes, fulfill campaign promises and reverse Trump administration policies, but also to reassert US global leadership and realign foreign policy to better service the middle class, Sullivan said.

"Everything" the Biden administration does when it comes to foreign policy will be examined as to whether it makes life "better, safer and easier for working families," Sullivan said.

Sullivan also said that Biden will announce that Secretary of Defense Lloyd Austin will lead a "global force posture review," and, while that review is ongoing, will "freeze any troop redeployments from Germany."

Biden is also expected to announce his intention to increase the number of refugees admitted into the United States after years of historical lows under the Trump administration, and fulfill a campaign promise in doing so, two sources familiar with the plans told CNN.

The Trump administration set a refugee cap of 15,000 for this fiscal year, the lowest since 1980. It's unclear by how much the Biden administration will increase that level, though the President has pledged to set an annual admissions cap of 125,000. Whatever the refugee cap level, it must be approved by the President.

'Restoring America's place in the world'

Biden's visit to America's oldest Cabinet agency is meant to thank a workforce repeatedly maligned under the previous administration. His remarks to them will center on the theme of "restoring America's place in the world," one of his central campaign promises.

The content and the symbolism of his appearance is meant to convey unmistakable signals: that this administration values diplomacy and its diplomats, it will center its foreign policy around cooperation with allies, and it will work to restore its reputation as a country that leads by example.

White House press secretary Jen Psaki said Wednesday that Biden's visit, which was rescheduled from earlier this week due to weather, "is largely focused on his desire to thank the men and women who are foreign service officers, civil servants, who are the heart and soul of that institution and frankly our government."

"Many of them have had a challenging couple of years," she added.

Blinken, a longtime Biden associate and veteran of the department, has sought to start his tenure by emphasizing the importance of the State Department's career workforce, whose expertise was oftentimes shirked and viewed with suspicion by a President who once called the agency "the Deep State Department."

Donald Trump visited the department just once in his four years in office for a ceremonial event. He repeatedly and publicly disparaged one of its most well-respected diplomats, Marie Yovanovitch, during the course of his first impeachment. His secretary of state, Mike Pompeo, failed to publicly or robustly defend her, deepening the decline in morale at Foggy Bottom.

Blinken pledged to have the backs of his workforce on his first full day as secretary of state, a commitment that US diplomats said was necessary after years of being denigrated. However, they have also said that actions will speak louder than words and it will take time to see exactly how the Biden administration lives up to its promises and elevates the diplomatic corps.

Both the President, his top diplomat and their top officials have repeatedly stressed that the most daunting challenges facing the US -- from the existential threat of climate change to the transnational threat of cyberattacks and near-peer competition from an increasingly aggressive China -- require allies to work together.

The administration is now undertaking a series of reviews of foreign policy challenges as it determines its own policy. However, Biden has indicated he will seek to frame his foreign policy around shoring up alliances and returning to multilateralism after the "America First" Trump era.

Biden has spoken by phone to more than a half-dozen foreign counterparts since taking office, while Blinken has been working the phones intensely to do outreach to his counterparts around the world.

A source close to both men has said that they are aware that there is serious repair work to be done after four years of the Trump administration left allies wary and bruised -- and uncertain about how reliable an ally the US will be in future.

"There's a real sense among allies is, 'How long can we count on them?'" said this source. "We have to address that."